Question
The average age of a group of
five friends is 78 years. If a friend, aged 48 years, is replaced by another friend, then the average age of each friend in the group will increase by 4 years. Find the age of the friend who was replaced.Solution
ATQ,
Sum of the ages of 5 friends, initially = 5 X 78 = 390 years Let the age of the new friend who joined the group = 'y' years Therefore, 390 - 48 + y = 5 X (78 + 4) Or, 'y' = 410 - 342 = 68 Therefore, age of the new friend = 68 years Alternate Solution Age of the new friend = age of the friend replaced + increase in average age X number of friends So, age of the new friend = 48 + 5 X 4 = 48 + 20 = 68 years
(30 × 0.80)⁴ ÷ (2160 ÷ 60)⁴ × (54 × 16)⁴ = (6 × 4)?+5
3/7 of 504 ÷ 12 + 17 = √?
20% of 150 + 30 X 4 = ? X 5
52% of 400 + √(?) = 60% of 600 - 25% of 400
135÷ 15 x 19 + 14807 = ? + √3249 - √9604
(22² × 8²) ÷ (92.4 ÷ 4.2) =? × 32
15 * 12 + 35% of 80 + 70% of 130 = ?
60 % of 640 - 57 × 2 - 1520 / 38 = ?
- Find the simplified value of the given expression:
10 of 5 ÷ 4 × 2² + √25 – 8 (168 ÷ 12 + 19 × 64)/(22+1) = ?