calculate how many days it will take for 5 boys to paint a 65 m long wall if 2 boys can paint a 40 m long wall in 4 days ,
"the length of wall painted by one boy in one day = 40 / 2 * 1 / 4 = 5 m no . of days required to paint 50 m cloth by 8 boys = 65 / 5 * 1 / 5 = 2.6 days . a"
divide(multiply(multiply(2, 4), 65), multiply(40, 5))