Answer:
Total number of boys at the concert=100
Step-by-step explanation:
The total number of boys and girls at the concert can be expressed as follows;
Total number of boys (b)=(ratio of boys/total ratio)×total number of boys and girls (t)
where;
Total number of boys=b
ratio of boys=2
total ratio=(2+7)=9
total number of boys and girls=t
replacing;
b=(2/9)×t...equation 1
The total number of girls (g)=Total number of boys (b)+250
g=b+250...equation 2
The value of b in equation 2 is replaced by the value of b in equation 1;
g=(2/9)t+250
And the total number can be expressed as;
Total number (t)=Total number of boys (b)+total number of girls (g)
t=b+g
where;
b=(2/9)t
g=(2/9)t+250
replacing;
t=(2/9)t+(2/9)t+250
t=(4/9)t+250
t-(4/9)t=250
(5/9)t=250
t=250×9/5
t=450
The total number of boys (b)=(2/9)t
replace t with 450
b=(2/9)×450
b=100
Total number of boys at the concert=100
