David had to paint some boxes. On the first day, the number of boxes he painted was 30% of the number of boxes that he had not painted. One week later, he painted another 165 boxes. As a result, the total number of painted boxes became 25 more than
12 of the total number of boxes. How many less boxes were painted than unpainted on the first day?
|
Painted |
Not painted |
Total |
Before
|
3x2 = 6 u |
10x2 = 20 u |
13x2 = 26 u |
Change |
+ 165 |
- 165 |
|
After |
6 u + 165 |
20 u - 165 |
26 u |
Comparing painted and not painted boxes in the end |
1x13 + 25 = 13 u + 25 |
1x13 - 25 = 13 u - 25 |
2x13 = 26 u |
30% =
30100 =
310Painted : Not painted = 3 : 10
The total number of boxes remains unchanged. Make the total number of boxes at first and in the end the same. LCM of 13 and 2 is 26.
The number of boxes painted in the end is repeated.
13 u + 25 = 6 u + 165
13 u - 6 u = 165 - 25
7 u = 140
1 u = 140 ÷ 7 = 20
Number of less boxes that were painted than not painted on the first day
= 20 u - 6 u
= 14 u
= 14 x 20
= 280
Answer(s): 280