40% of the children at a childcare centre are boys. If there are 18 more girls than boys, how many children are there?

Suppose there are X children at the childcare.

Thus :

boys + girls = X

40% of the children are boys .

Thus :

There are 40/100 × X boys .

So : boys = 0.4X (( Ω ))

There are 18 more girls than boys

Thus :

girls - boys = 18

girls - ( 40/100 X ) = 18

girls - 0.4X = 18

Add sides 0.4X

girls - 0.4X + 0.4X = 18 + 0.4X

girls = 18 + 0.4X (( μ ))

Now It's time to put (( μ ))

and (( Ω )) in the above equation.

boys + girls = X

0.4X + 18 + 0.4X = X

0.8X + 18 = X

Subtract sides 0.8X

- 0.8X + 0.8X + 18 = 1X - 0.8X

18 = 0.2X

0.2X = 18

Divided sides by 0.2 (( 2/10 ))

2/10 ÷ 2/10 × X = 18 ÷ 2/10

X = 18 × 10/2

X = 18 × 5

X = 90

Thus there are 90 children at the childcare.

Done♥️♥️♥️♥️♥️

Thank you!! ^^

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