Question: A person puts $5600 in a bank for two years. Each year he earns interest of 7% of the original amount deposited. How much will this person have in the bank after two years?
Answer with step-by-step thinking: The interest that this person will get equals $5600 * 7% / year * 2 years = $784. After two years the amount found at the bank is $5600 + $784 = $6384.
So the answer is 6384.

Question: Janet makes $20 per hour at work. She works 52 hours per week. Anything over 40 hours per week is considered overtime and is paid at 1.5 times the normal rate. She wants to purchase a $4640 car. How many weeks does she need to work to purchase the car?
Answer with step-by-step thinking: Each week she makes $20 * 40 = $800 from her normal hours. For overtime she makes $20 * 1.5 = $30 per hour. Each week she works 52 - 40 = 12 overtime hours per week. She makes a total of 12 * $30 = $360 from overtime every week. This means she makes a total of $800 + $360 = $1160 per week. To reach $4640 she would need to work $4640 / $1160 = 4 weeks.
So the answer is 4.

Question: Jason is mixing a batch of black paint. He needs to add 2 grams of charcoal for every 30 ml of water. If he adds 900 ml of water, how much charcoal does he add?
Answer with step-by-step thinking:
First find how many ml of water Jason needs for 1 gram of charcoal: 30 ml / 2 grams = 15 ml / g. Then divide the amount of water Jason uses by the amount of water per gram of charcoal to find how much charcoal he uses: 900 ml / 15 ml / g = 60 g.
So the answer is 60.