JAMB - Mathematics (1979 - No. 6)
After getting a rise of 15%, a man's new monthly salary is N345. How much per month did he earn before the increase?
N330
N396.75
N300
N293.25
N360
Explicació
Let x represent his monthly salary before increase 15% of
x = 345
% profit = (100 + 15)%
= 115%
\(\frac{115}{100}\)x = 345
115x = 34500
x = N300.00