Percentage Questions in English

(D) Abhinav's investment $= ₹ 6,000$.
Sunil's investment $= 6,000 - (30 \% \text{ of } 6,000) = 6,000 \times 0.70 = ₹ 4,200$.
Rita's investment $= 4,200 + (25 \% \text{ of } 4,200) = 4,200 \times 1.25 = ₹ 5,250$.
Total amount invested $= 6,000 + 4,200 + 5,250 = ₹ 15,450$.
Required ratio $= \frac{\text{Rita's investment}}{\text{Total investment}} = \frac{5,250}{15,450}$.
Dividing both by $150$,we get $\frac{5,250 \div 150}{15,450 \div 150} = \frac{35}{103}$.
Thus,the ratio is $35:103$.

(D) To solve the expression $15 \%$ of $578 + 22.5 \%$ of $644$:
Step $1$: Calculate $15 \%$ of $578$.
$15 \% \times 578 = 0.15 \times 578 = 86.7$.
Step $2$: Calculate $22.5 \%$ of $644$.
$22.5 \% \times 644 = 0.225 \times 644 = 144.9$.
Step $3$: Add the two results.
$86.7 + 144.9 = 231.6$.
Therefore,the correct answer is $231.6$.

(B) Let the amount invested by Raghu be $₹ x$.
Since Mona invested $10 \%$ less than Raghu,the amount invested by Mona is $x - 0.10x = 0.9x$.
Since Sonu invested $10 \%$ more than Mona,the amount invested by Sonu is $0.9x + 0.10(0.9x) = 0.9x + 0.09x = 0.99x$.
The total sum of their investments is given as $₹ 5,780$.
Therefore,$x + 0.9x + 0.99x = 5,780$.
$2.89x = 5,780$.
$x = \frac{5,780}{2.89} = 2,000$.
Thus,Raghu invested $₹ 2,000$.