At a certain stationery store, ruler is sold at 91 yen, pen at 117 yen, pencil at 40 yen and notebook at 143 yen, respectively.
Taro bought these four items at least one piece each.
The total cost was 680 yen.
Find the number of pencil he bought.
Answer
4 pieces
Solution
91,117,143 are multiples of 13.
Taro bought these four items at least one piece each.
The total cost was 680 yen.
Find the number of pencil he bought.
Answer
4 pieces
Solution
91,117,143 are multiples of 13.
When 40 is divided by 13, 1 remains.
In other words, every time one pencil is bought additionally, the remainder would be increased by 1.
680/13 = 52 with remainder 4.
Therefore the number of pencil he bought is 4.
