The answer is 64 boys are in the soccer league.
X/160 = 40/100
X/160 * 100 = 40/100 * 100
5x/8 = 40
(8 * 5x)/8 = 40 * 8
5x = 320
5x/5 = 320/5
x = 64
A and C
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A varible represents the number u are looking for.
Example:
2x + 3x
Add up them up
Ab+BC
18.3+11.2
=29.5
Difference means subtract, so we use subtraction:
*first we need to make the fractions have the same denominator
1/4 = 3/12
2/3 = 8/12
126(3/12) - 78(8/12)
*since the fraction in the first term is smaller than the second, make it improper
125(15/12) - 78(8/12)
now simply subtract:
125 - 78
= 47
15 - 8
= 7
* this is now (7/12)
now put them back together:
47(7/12)
That's the final answer!