Answer:
7 girls
Step-by-step explanation:
The ratio of boys : girls = 7 : 1 = 7x : x ( x is a multiplier )
There are 42 more boys than girls, thus
7x = x + 42 ( subtract x from both sides )
6x = 42 ( divide both sides by 6 )
x = 7
Hence
there are 7 girls
and 7x = 7 × 7 = 49 boys