150% of the number A is equal to half of the number B. If 3 is added to number A, then the number A becomes 180 of its reciprocal. Find the number B?
A. 20
B. 48
C. 64
D. 36
E. None of these
Sol:
Let the number A = 2x
And the number B = 2x * 150/100 * 2/1 = 6x
2x + 3 = 180 * 1/2x
(2x + 3) * 2x = 180
4×2 + 6x – 180 = 0
2×2 + 3x – 90 = 0
2×2 – 12x + 15x – 90 = 0
2x(x – 6) + 15(x – 6) = 0
x = +6, -15/2
x = 6
The number B = 6 * 6 = 36
