Question

Sacha picked some apples from a tree in her garden. She then gave some to her friends. To her
first friend, she gave half the apples she had, plus 2 more. To her second friend, she gave half the apples she had left, plus 2 more. And she did the same thing for her third friend. After giving away all these apples, she had 1 apple left. Find how many apples she originally pick from the tree.

Answer 1

Step-by-step explanation:

x = apples picked from the tree

x1 = x/2 + 2

x2 = (x - x1)/2 + 2 = (x - (x/2 + 2))/2 + 2 =

= (x - x/2 - 2)/2 + 2 = (x/2 - 2)/2 + 2 =

= x/4 - 1 + 2 = x/4 + 1

x3 = (x - x1 - x2)/2 + 2 = (x - (x/2 + 2) - (x/4 + 1))/2 + 2 =

= (x - x/2 - 2 - x/4 - 1)/2 + 2 =

= (x/4 - 3)/2 + 2 = x/8 - 3/2 + 2 = x/8 + 1/2

x - x1 - x2 - x3 = 1

x - x/2 - 2 - x/4 - 1 - x/8 - 1/2 = 1

x/8 - 3 - 1/2 = 1

x/8 = 4 1/2 = 9/2

x = 9×8/2 = 9×4 = 36

she had originally 36 apples

x1 = 20

x2 = 10

x3 = 5