Because they have the same amount of child tickets, You would take the amount more Josh spent and divide it by how many more adult tickets he bought. Amount more he spent-$15 and he bought 2 extra adult tickets so $7.50 each. If an adult ticket is $7.50. $25-$7.50(one adult ticket)=$17.50/5(# of child tickets)=$3.50
Adult price-$7.50
Child price-$3.50