Jack had to paint some boxes. On the first day, the number of boxes he painted was 40% of the number of boxes that he had not painted. One week later, he painted another 172 boxes. As a result, the total number of painted boxes became 16 more than
34 of the total number of boxes. How many more boxes were unpainted than painted on the first day?
|
Painted |
Not painted |
Total |
Before
|
2x4 = 8 u |
5x4 = 20 u |
7x4 = 28 u |
Change |
+ 172 |
- 172 |
|
After |
8 u + 172 |
20 u - 172 |
28 u |
Comparing painted and not painted boxes in the end |
3x7 + 16 = 21 u + 16 |
1x7 - 16 = 7 u - 16 |
4x7 = 28 u |
40% =
40100 =
25Painted : Not painted = 2 : 5
The total number of boxes remains unchanged. Make the total number of boxes at first and in the end the same. LCM of 7 and 4 is 28.
The number of boxes painted in the end is repeated.
21 u + 16 = 8 u + 172
21 u - 8 u = 172 - 16
13 u = 156
1 u = 156 ÷ 13 = 12
Number of more boxes that were not painted than painted on the first day
= 20 u - 8 u
= 12 u
= 12 x 12
= 144
Answer(s): 144