Answer:
30.0%
Step-by-step explanation:
0.63×0.23=0.1449≈14.5% approx 14.5%
Therefore, 14.5% of all students at the school are girls who wear contacts.
Let's repeat this for boys by multiplying the percent of boys at the school by the percent of boys that wears contacts.
0.37×0.42=0.1554≈15.5% approx 15.5%
Therefore, 15.5% of all students at the school are boys who wear contacts.
0.145+0.155=0.3=30.0%
30.0% of all the students wear contacts.