Question

A king is planning to build a tomb that would take ten masons ten days. Unfortunately, on the first
day only 1 mason is available. On the second day two more join. This continues, with 2 more masons
joining in the work every day till the work is complete. How many days will it take to build the tomb?​

Answer 1

Answer:

it will take 10 days to build the tomb

Step-by-step explanation:

a tomb would take ten masons ten days

=> total Mason days required = 10 * 10  = 100

On 1st Day 1 mason is availbe

so work done = 1 mason day

on second day   1 + 2 = 3 Masons available

so work done = 3 Mason Day

on third day = 3 + 2 = 5 Masons available

so work done = 5 Mason Day

1 + 3 + 5  + ..................................+ (2n-1)  = 100

(n/2)(1 + 2n - 1) = 100

=> (n/2)(2n) = 100

=> n² = 100

=> n = 10

Hence it will take 10 days to build the tomb