Class - IX
Subject: General Mathematics
Time : 3 hrs. Marks. 100
Answer any one 5x1=5
1. (i) Determine the set of natural numbers which on dividing 605 and 821 leaves 29 as remainder in each case.
(ii) If U = { 1, 2, 3, 4, 5, 6 }
A = { 1, 3, 5, }
B = { 2, 4, 6 }
C = { 2, 3, 4, 5 }
then prove that ( AUBUC)
= A



(iii) IF ( x+y, a2 -b2 ) = ( a+b, ax -by ) then find (x, y ).
2. prove that,
is an irrational number. 5x1=5

3. Answer any two : 3x2=6
(i) If x +
= 4 then find the value of
.


(ii) If (x+y)2 =3 and ( x-y)2 =2 then prove that 2xy (x2+y2) = 

(iii) If x =
then find the value of x2 +


(iv) If x +y =a, x2 + y2 = b and x3 + y3 = 3ab then prove that, a3 + 2c3 =3ab
4. Resolve into factors : any two 2x2=4
(i) x2 - x - ( a2 +5a +6)
(ii) (a-1) x2 + a2xy + ( a+1) y2
(iii) 2a3 + 3a2b + 3ab2 - 8b3
(iv) (x + 1) (x + 3) ( x+5) (x +7) +15
5. Answer any one : 5x1=5
(i) (x+2) is a factor of x2 + px +q and x2 +p x +q then prove that, 

(ii) Find the H. C. F of the following a3 -1, a3+1, a4 +a2 +1, (a+1)2
(iii) If the L. C. M and H. C.F. of the two numbers are x3 - 10x2 + 11x +70 and ( x-7) respectively
and one of the number is x2 -5x -14 then find the other number.
6. Answer any two : 5x2=10
(i) At 4% profit it the difference of simple and compound profit for 2 years is TK. 1 then
find the capital?
(ii) Purchasing 2 oranges at Tk. 5. How many oranges are to be sold at Tk. 75 to make a profit
of a% ?
(iii) The salary of Mr. Matin is x% higher than that of Mr. Jalil. As a result the salary of Mr. Jalil
is y% less than that of Mr. Matin. Express y as a function of x.
(iv) A boat man can row d km in t2 hours against the current. To cover the same distance he takes
t1 hours in favour of the current. What are the speeds of the current and the boat?
7. Answer any one : 5x1=5
(i) 

(ii) 

8. Answer any two : 5x2=10
(i) If
then prove that x, y, z are in continued proportion.

(ii) If
=
=
then prove that, 




(iii) Solve :

(iv) If a, b, c are in continued proportion then prove that, a2 b2 c2 (
) = a3 + b3 +c3

9. Answer any two : 5x2=10
(i) If the length fo each side of a square is increased by 5% then what is the percentage of increase in the area enclosed by the square?
(ii) 3 benches in a class room remain vacant, if 4 students sit in each bench. But 4 students are to remain standing if 3 students sit in each bench. What is the number of the students in that class?
(ii) A man covered some distance at the rate of 40km/hour and the rest at the rate of 60km/hour. He covered a total distance of 240 km in 5 hours. How far did he travel in 40km/ hour?
(iv) The hypotenuse of a right angled triangle is 10 cm and its perimeter is 24 cm. What is the area of the triangular region?
(v) A man bought some pens at Tk. 240 if he would have got 1 more pen then the price of each pen have been less by Tk. 1 on the average. How many pens did he buy?
10. Answer any one : 5x1=5
(i)
+
(ii) ( a +b +x)-1 = a-1 +b-1 +x-1


(iii)

11. Answer any one : 5x1=5
(i) Prove that, the locus of a point equidistant from given two points is the perpendicular bisector of the st. line joining the given points.
(ii) Prove that, equal chords of a circle are equidistant from the centre.
12. Answer any one : 5x1=5
(i)
ABC is a right angled isosceles triangle. P is any point on the hypotens BC. prove that

PB2 + PC2 =2 PA2.
(ii) In interior of a circle two chords AB and CD intersect at the point E. Prove that the sum of
the angles subtended by the arcs AC and BD of the centre is twice
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