Adam has some red stickers and green stickers.
The number of red stickers is increased by 10% to 77.
The number of green stickers is increased by 20% to 78.
- How many stickers are there at first?
- How many stickers are there in the end?
|
Red |
Green |
Before |
100% |
100% |
Change |
+ 10% |
+ 20% |
After |
110% = 77 |
120% = 78 |
(a)
100% + 10% = 110%
110% of red stickers = 77
100% of red stickers =
77110 x 100 = 70
100% + 20% = 120%
120% of green stickers = 78
100% of green stickers =
78120 x 100 = 65
Number of stickers at first
= 100% of red stickers + 100% of green stickers
= 70 + 65
= 135
(b)
Number of stickers in the end
= 77 + 78
= 155
Answer(s): (a) 135; (b) 155