In a store, some toy planes and frisbees were on sale.
110 of the items were toy planes.
13 of the toy planes and 770 frisbees were sold. There were
19 of the items left in the store. How many toy planes and frisbees were there in the store at first?
| |
Toy planes |
Frisbees |
Total |
Comparing toy planes
and frisbees at first |
1x9 =
9 u |
9x9 =
81 u |
10x9 =
90 u |
| Before |
3x3 =
9 u |
|
9x10 =
90 u |
| Change |
- 1x3 =
- 3 u |
- 770
|
- 8x10 =
- 80 u |
| After |
2x3 =
6 u |
4 u |
1x10 =
10 u |
The total number of toys at first is repeated. Make the total number of toys at first the same. LCM of 10 and 9 is 90.
The number of toy planes at first is repeated. Make the number of toy planes the same. LCM of 9 and 3 is 9.
Number of frisbees left
= 10 u - 6 u
= 4 u
Number of frisbees sold
= 81 u - 4 u
= 77 u
77 u = 770
1 u = 770 ÷ 77 = 10
Number of toy planes and frisbees at first
= 90 u
= 90 x 10
= 900
Answer(s): 900
