Risa had some pens at first. She gave 19 of her pens to her sister and 23 of her pens to her neighbour. After that, her mother gave her another 12 pens. She had 26 pens in the end. How many pens did Risa have at first?
Fraction of pens left after giving to her sister and her neighbour
= 1 -
19 -
23 = 1 -
19 -
69 = 1 -
79 =
29 Number of pens left after giving to her sister and her neighbour = 2 u
Number of pens left after her mother gave her another 12 pens = 2 u + 12
2 u + 12 = 26
2 u = 26 - 12
2 u = 14
1 u = 14 ÷ 2 = 7
Number of pens that Risa had at first
= 9 u
= 9 x 7
= 63
Answer(s): 63
