CBSE math

CBSE maths CBSE Sample Guess Question Papers CBSE hindi social science results X X11 syllabus



Question16. I need CBSE maths new paper pattern.  by Ashmita class X answered on Jan 9, 2007 at 8:00 a.m. (+ 5.5 G.M.T.)
Answer16.   You can download it from here click here

Question17. Can i get full information about project work of 10th board exam? by sunny kejriwal answered on Jan 10, 2007 at 9:08 p.m. I.S.T.
Answer17.  Sure, you can download Maths Lab Manual from here. click here
The Project work in maths carries 5 marks and out of 5 project you have to make one project. If after going through the Lab manual if you have any doubt feel free to contact us again.

Question18. Find the value of p for which the points (-5,1),(1,p),(4,-2) are collinear. by Chandini class x answered on Jan 11, 2007 at 10:15 I.S.T.
Answer18.  Let (1,p) divides the join of
(-5,1) and (4,-2) in ratio k:1. Using section formula 1 = (4k - 5)/(k+1)
                k = 2
                p = (- 2k+1)/(k+1)  
                p = - 1

Question19. Can you please tell what is Siddhacharyas formula? by ravikant class X answered on Jan 12, 2007 at 7:40 p.m. I.S.T.
Answer19.   Quadratic formula is called Siddhacharyas formula.

Question20. Find probability of 53 Sundays in a leap year. by Simran class x, answered on Jan 13, 2007 at 8:15 a.m.
Answer20. Total days in a leap year is 366. (366/7) = 52 2/7. So there are 52 sundays the remaining two days can be any two consecutive days for example sunday and monday. Out of the total outcomes thus obtained 2 contain sunday.So the Probability of 53 sundays in a leap is 2/7.

Question21. I have not recieved the answer of my 9th class question. i had asked the question in  last week.by Hitesh Kumar class 1x, answered on Jan 14, 2007 at 9:00 p.m. I.S.T.
Answer21.  At this time we are answering only one question per day, so we are not able to answer all questions we receive . These questions are more than 50 per day. You have second time so we will try to answer your question at the earliest.

Question22. Sum of 3 terms  of an A.P. is 3 and product is - 24. Find the three of A.P. by Aakansha  class x, answered on Jan 17, 2007 at 10:00 p.m. I.S.T.
Answer22. Let the 3 terms be a + d, a, a + d
               Sum =
a + d  + a  +  a + d = 3
               3a = 3
               a = 1
               Product = (a + d)a(a - d) = - 24
               (1 + d)1(1 - d) = - 24  (since a = 1)
               1 - d^2 = - 24
               d = +- 5
               Terms of A.P. are -4, 1, 6 or 6, 1, - 4

Question23. I want your suggestion for my son about maths for comming exam cbse final 2007 by Arup Kr, Das, answered on Jan 19, 2007 at 5:31 p.m. I.S.T.
Answer23.  For maths exam suggestion refer this page click here . If you have any other question write to us once again through the same form.

Question24. Find the sum of first hundred even positive integers divisible by 5 by Debanik Bhattacharjee answered on Jan 20, 2007 at 8:05 a.m. I.S.T. ( +5.5 G.M.T.)
Answer24. A.P. of reqd. numbers is 10, 20, 30, 40, .........
               Here first term = a = 10, common difference = d = 10
               100th term = a + 99 d
                = 1000
               Sum of 100 terms n/2(a + l) where l is last term
                = 100/2(10 + 1000)
                = 50500

Question25. Sum of 3terms of A.P. is 36 and product is 1296. Find A.P? by mohammed noufal answered on Jan 21, 2007 at 9:43 p.m. I.S.T.
Answer25. This type of question has been answered (see Q 22)

Question26. solve for x:(x-3)(x+9)(x-7)(x+5)=208 by kanika khanna                                                         Email kanikakhanna............@hotmail.com   answered on 22.1.07 at 8:43 p.m.
Answer 26. These type of questions do not form part of the current class x syllabus. But still we are giving the solution.
                Step 1  rearrange
(x+9)(x-7)(x-3)(x+5) = 208
                Step 2  (x^2 + 2x - 63)(x^2 + 2x - 15) =
208
                Step 3  Put x^2 + 2x = y
                Step 4  (y - 63)(y - 15) =
208
                Step 5  y^2 - 78y + 945 = 208
                Step 6  y^2 - 78y + 737 = 0
                Step 6  (y - 7)(y - 71) = 0
                Step 7  y = 7, y = 71
                Step 8  putting value of y we get
x^2 + 2x = 7 or x^2 + 2x = 71 now we solve for x

We are back after Republic day break and will start answering questions from today. Posted on Jan 30,2007 at 9:04 I.S.T.
Question27. find the weight of a lead pipe 3.5m iong if the external diameter of the pipe is 2.4m and the thickness is 2mm and 1 cubiic  cm of lead weighs 11g by chaitanya kaul class x, Email add chaitanya................@gmail.com, answered on Jan 31, 2007 at 7:32 I.S.T.
Answer 27. Height = 3.5m = 3500 mm, outer radius (R) = 1.2 m = 1200 mm, Inner radius(r) = 1200 - 2 = 1198 mm
                Volume = outer volume - inner volume = Pie h (R^2 - r^2) = (22/7) 3500 (1200^2 - 1198^2)
                = 22*500(1200 - 1198)(1200 + 1198)     using identity
                = 22*500*2*2398
                = 22*1000*2398
                = 52756000 mm^3
                = 52756 cm^3
                Density = 11g/cm^3
                Mass = Volume * density = 52756*11
                =  580316 grams or 580.316 k.g.

Question28. An isosceles triangle ABC is inscribed in a circle. If AB = AC = 13cm and BC = 10cm,find the radius of the circle. by Francis Thomas class x/1x, Email add francis..............@yahoo.co.in answered on Feb 1, 2007 at 11:08 p.m. I.S.T.
Answer 28. Draw AD perpendicular to BC intersecting BC at D.
                AD bisects BC , So BD =
½ BC = ½(10) = 5cm
(since altitude to base in an isosceles triangle is also median)
                So AD becomes perpendicular bisector of BC and hence passes through centre of circle let it be O
               (since perpendicular bisector of a chord passes through centre of circle.)

                In right triangle ADB, AB^2 = AD^2 + BD^2 (pythagoras theorem)
                                  13^2 = AD^2 + 5^2
                                  169 = AD^2 + 25
                                   AD^2 = 169 - 25
                                   AD = 12 cm.
                                   Let radius OA = x cm.
                                   OD = (12 - x) cm.
                                   OB = OA = x cm.(radii of same circle)
                                   In right triangle BDO, OB^2 = OD^2 + BD^2
                                   x^2 = (12 - x)^2 + 5^2
                                   x^2 = 144 + x^2 - 24x + 25
                                   24x = 169
                                   x = 169/24
                                   Radius = 169/24 cm.


Question29.
find the weight of a lead pipe 3.5m iong if the external diameter of the pipe is 2.4m and the thickness is 2mm and 1 cubiic  cm of lead weighs 11g by chaitanya kaul class x, Email add chaitanya................@gmail.com, answered on Jan 31, 2007 at 7:32 I.S.T.
Answer29. Height = 3.5m = 3500 mm, outer radius (R) = 1.2 m = 1200 mm, Inner radius(r) = 1200 - 2 = 1198 mm
              
Volume = outer volume - inner volume = Pie h (R^2 - r^2) = (22/7) 3500 (1200^2 - 1198^2)
               = 22*500(1200 - 1198)(1200 + 1198)     using identity
               = 22*500*2*2398
               = 22*1000*2398
               = 52756000 mm^3
               = 52756 cm^3
               Density = 11g/cm^3
               Mass = Volume * density = 52756*11
               =  580316 grams or 580.316 k.g.

Question30. An isosceles triangle ABC is inscribed in a circle. If AB = AC = 13cm and BC = 10cm,find the radius of the circle. by Francis Thomas class x/1x, Email add francis..............@yahoo.co.in answered on Feb 1, 2007 at 11:08 p.m. I.S.T.
Answer30. Draw AD perpendicular to BC intersecting BC at D.
               AD bisects BC , So BD =
½ BC = ½(10) = 5cm
(since altitude to base in an isosceles triangle is also median)
               So AD becomes perpendicular bisector of BC and hence passes through centre of circle let it be O (since perpendicular 
               bisector of a chord passes through centre of circle.)

               In right triangle ADB, AB^2 = AD^2 + BD^2 (pythagoras theorem)
                                  13^2 = AD^2 + 5^2
                                  169 = AD^2 + 25
                                   AD^2 = 169 - 25
                                   AD = 12 cm.
                                   Let radius OA = x cm.
                                   OD = (12 - x) cm.
                                   OB = OA = x cm.(radii of same circle)
                                   In right triangle BDO, OB^2 = OD^2 + BD^2
                                   x^2 = (12 - x)^2 + 5^2
                                   x^2 = 144 + x^2 - 24x + 25
                                   24x = 169
                                   x = 169/24
                                   Radius = 169/24 cm.




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