Question

The number of students studying Physics, Chemistry, and Zoology are in the ratio $4:3:5$. If the numbers in these three disciplines increased by $50%$, $25%$, and $10%$ respectively in the next year, what is the new respective ratio?

• A. $24:15:22$
• B. $18:11:13$
• C. $24:13:17$
• D. CANNOT BE DETERMINED

Hint:

When ratios change by percentages, multiply each term by $(1+\textrate)$ and finally clear decimals by a common factor to get the simplest integer ratio.

Answer 1

The Correct Option is A

Step 1: Apply the given percentage increases to each term.
Physics: $4 \times (1+0.50) = 4 \times 1.5 = 6$.
Chemistry: $3 \times (1+0.25) = 3 \times 1.25 = 3.75$.
Zoology: $5 \times (1+0.10) = 5 \times 1.10 = 5.5$.
Step 2: Clear decimals to get a clean ratio.
$6 : 3.75 : 5.5 \ ⇒\ \times 4 ⇒\ 24 : 15 : 22$. \[ \boxed{24:15:22} \]