A class had 14 boys with an average height of 5.3 feet. A new boy joined the class. Now the average of the 15 boys in the class was 5.25 feet. How tall was the new boy?
- 4.55 feet
- 5.55 feet
- 3.55
- None of these
Explanation
Initially, the total height of the 14 boys = Average height x Number of boys = 5.3 x 14 = 74.2 feet
After the new boy joined, the total height of the 15 boys = New average height x Total number of boys = 5.25 x 15 = 78.75 feet
Since the total height increased by the height of the new boy, we can set up the equation:
74.2 + New boy's height = 78.75
Subtract 74.2 from both sides:
New boy's height = 78.75 - 74.2
New boy's height = 4.55 feet
So, the new boy's height is 4.55 feet.
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