You'd start off by adding the 2 adults together (10.75 + 10.75) which would equal 21.50 dollars. Now you take the three kids together (5.50 +5.50+5.50) which would equal 16.50 dollars.
Now you just take the 16.50+21.50 and add those together---- 38 dollars
Step-by-step explanation:
Take the number as x
12x-40=7x+25
collect like terms
12x-7x=25+40
5x=65(divide both sides by 5)
x=13
Therefore number is 13