The average height of 45 sticks is 157 cm. Some sticks of average height 163 cm are taken out. If the new average height is 153 cm, then how many sticks are left?
The average height of 45 sticks is 157 cm. Some sticks of average height 163 cm are taken out. If the new average height is 153 cm, then how many sticks are left? Correct Answer 27
Given:
Average height of 45 sticks = 157 cm
New average height of the sticks after removing some sticks of height 163 cm = 153 cm
Formula used:
Average of n numbers = Sum of all the numbers/n
Calculation:
Total height of all the sticks initially = 45 × 157 = 7065
Let n number of sticks were removed
⇒ Total height of removed sticks = 163n
Also, according to the question:
Total height of remaining sticks = (45 - n)(153) = 6885 - 153n
Then, 7065 = 6885 - 153n + 163n
⇒ 180 = 10n
⇒ n = 18
∴ Remaining sticks = 45 - 18 = 27.
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Feb 20, 2025