a monkey start climbing up a tree 21 ft tall . each hour it hops 3 ft and slips back 2 ft . how much time would it take the monkey to reach the top .
"if monkey hops 3 ft and slips back 2 ft in a hour , it means the monkey hops ( 3 ft - 2 ft ) = 1 ft / hr . similarly in 18 hrs it wil be 18 ft . but since the height of the tree is 21 ft , so if the monkey hops up the tree in the next hr i . e 19 th hr then it reaches at the top of the tree . hence it takes 19 hrs for monkey to reach at the top answer : c"
subtract(divide(21, subtract(3, 2)), 2)