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A ladder has rungs 25 cm apart, (see Fig...

A ladder has rungs 25 cm apart, (see Figure). The rungs decrease uniformly in length from 45 cm at the bottom to 25 cm at the top. If the top and the bottom rungs are `2 1/2`m apart, what is the length of the wood required for the rungs?

Text Solution

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Length of rugs is in AP
n=250/25=10
therefor, number of rugs=10
`S=r_1+r_2+...+r_10`
`S_10=10/2(a+l)`
`S_10=5(45+25)`
`S_10=350 cm`
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