Three numbers are in the ratio 4: 5: 6 and their average is 40. The largest number is :-
- AOption (a)
44
- BOption (b)
42
- COption (c)
48
- DOption (d)
32
View answer & explanationHide answer & explanation
Correct answer
48
Why this answer is correct
Shortcut Trick
Ratio of numbers = 4 : 5 : 6
Since the numbers are in Arithmetic Progression, the Average is the middle term (5 units).
5 units = 40 ⇒ 1 unit = 8
Largest number (6 units) = 6 × 8 = 48
∴ The correct answer is 48.
Alternate Method
Given: Ratio = 4 : 5 : 6, Average = 40
Formula: Average = Sum of observations ÷ Total number of observations
⇒ Let the numbers be 4x, 5x, and 6x.
⇒ (4x + 5x + 6x) ÷ 3 = 40
⇒ 15x ÷ 3 = 40
⇒ 5x = 40
⇒ x = 8
⇒ Largest number = 6x = 6 × 8 = 48
∴ The correct answer is 48.
Additional Information
Average of AP
For any series in Arithmetic Progression, the Average is equal to (First term + Last term) ÷ 2 or the middle term if the number of terms is odd.
Ratio and Proportion
If quantities are in ratio a : b : c, their values can be assumed as ax, bx, and cx where x is the highest common factor.