If 102y = 25, then 10-y equals: (a) -1/5, (b) 1/625, (c) 1/50, (d) 1/25, (e) 1/5 - Maths - Ratio and Proportion

Question

If 102y = 25, then 10-y equals:

(a) -1/5, (b) 1/625,
(c) 1/50, (d) 1/25, (e)
1/5

Adarsh Saini · Accepted Answer

102y = 25

(10y)2 = 52

10y = 5

1/10y =
1/5

10-y = 1/5

Answer: (e)