Question

If t and m are positive, t^2 + m^2 = 64 and (t+m)^2 = 98, what is tm?

(A) 162
(B) 130
(C) 81
(D) 34
(E) 17

Answer 1

17

Explanation:

t^2 + m^2 = 64

(t+m)^2 = 98

(t+m)^2 = t^2 +2tm+ m^2

==>

t^2 +2tm+ m^2 = 98

t^2+m^2+2tm=98

64+ 2tm=98

2tm = 98 -64

2tm=34

tm= 34/2

tm = 17