Question

please explain the question...

Answer 1

let the number of persons in the start be x .

let the total work be '1 units'


x × 72/ 1 = (x - 21) × ( 72 + 54) / 1



72x = (x - 21)126

72x = 126x - 2646


126x - 72x = 2646

54x = 2646


x = 49


Answer:
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Number of persons in the start was 49.