In a college, the number of students studying Arts, Commerce, and Science are in the ratio of 4 : 7 : 9. If the number of students in Arts, Commerce, and Science increases by 30%, 20%, and 40% respectively, what will be the new ratio?

Correct option is C

Ans. (b)
Sol.
Original ratio = 4 : 7 : 9
Apply the percentage increase to each:
Arts: 4 + 30% of 4 = 4 + (30/100)×4 = 4 + 1.2 = 5.2
Commerce: 7 + 20% of 7 = 7 + (20/100)×7 = 7 + 1.4 = 8.4
Science: 9 + 40% of 9 = 9 + (40/100)×9 = 9 + 3.6 = 12.6
Now simplify the ratio 5.2 : 8.4 : 12.6
Multiply all by 5 to remove decimals:
= (5.2×5) : (8.4×5) : (12.6×5)
= 26 : 42 : 63
So, the correct ratio is 26 : 42 : 63