CSC Company Numerical Ability Algebra

If a - b = 3 and a2 + b2 = 29, find the value of ab.

A.10
B.12
C.15
D.18

Read Solution (Total 2)

If a - b = 3 and a^2 + b^2 = 29,

a-b=3
a^2 + b^2 -2*ab = 9,
29-2*ab =9
2ab=20
ab=20/2=10 ... option A
13 years agoHelpfull: Yes(8) No(4)

(a-b)^2=(a2+b2-2ab)
9=(29-2ab). So ab =10..
9 years agoHelpfull: Yes(0) No(0)

CSC Other Question

There are two examinations rooms A and B. If 10 students are sent from A to B, then the number of students in each room is the same. If 20 candidates are sent from B to A, then the number of students in A is double the number of students in B. The number of students in room A is:

A. 20
B. 80
C. 100
D. 200
A and B entered into partnership with capitals in the ratio 4 : 5. After 3 months, A withdrew 1/4 of his capital and B withdrew 1/5 of his capital. The gain at the end of 10 months was Rs. 760. A's share in this profit is:

A. Rs. 330
B. Rs. 360
C. Rs. 380
D. Rs. 430