Zach is saving his money to buy a brand new bike that costs $100. His weekly allowance is $5. His parent will pay him an extra $10 to mow the lawn. His neighbor will pay him $7 per hour to babysit their son. He has already saved up $65. He'll receive his allowance on Friday and he's planning on babysitting for 2 hours this Saturday after he mows the lawn. How much more money does Zach need to earn before he can buy the bike? Let's be accurate as possible.
If he babysits for 2 hours at $7 per hour, he will earn 2 * 7 = $14. This week he will earn $5 allowance, $10 mowing the lawn and $14 from babysitting for a total of 5 + 10 + 14 = $29. If we add the $29 he will earn to his $65 savings, he will have a total of 29 + 65 = $94. The bike costs $100 and he will have $94 leaving $100 - $94 = $6 more that he will need to earn.
The answer: 6.