Last night, Olive charged her phone for 10 hours. Assuming each hour of charge lasts the phone 2 hours of use, calculate the total time Olive would be able to use her phone before it goes off if she charges it for 3/5 of the time she charged the phone last night. Let's answer step by step:
If Olive charges her phone for 3 / 5 of the time she charged the phone last night, the phone would be charged for 3 / 5 * 10 = 6 hours. Assuming each hour of charge lasts the phone 2 hours of use, the phone will last for 6 * 2 = 12 hours before it goes off when Olive uses it on a six hours charge. The answer: 12.