Question

A man earns x% on the first Rs 2000 and y% on the rest of his income If he earns Rs 700 from Rs 4000 and Rs 900 from Rs 5000 of income find x%

• A. 20%
• B. 15%
• C. 25%
• D. None of these

Answer 1

The correct option is B 15%

When total income is Rs.$4000$, a man earns $x$ on first Rs.$2000$ and $y$ on Rs.$2000$.
$\frac{2000x}{100}+\frac{2000y}{100}=700$
$=20x+20y=700$
$=2x+2y=70$ (i)
When total income is Rs. $5000$, a man earns $x$ on first Rs.$2000$ and$y$ on Rs.$3000$.
$\frac{2000x}{100}+\frac{3000y}{100}=900$
$=20x+30y=900$
$=2x+3y=90$ (ii)
Subtracting (ii) from (i) we get,
$2x+3y=90$
$2x+2y=70$
- - -
$y=20$
Putting the value of $y$ in equation (i) we get,
$=>2x+2y=70$
$=>2x+2.20=70$
$=>2x=70-40$
$=>x=\frac{30}{2}$
$=>x=15$
A man earns $15$percent.