4 roommates are living in an apartment, then 2 of them leave. After 49 days, the remaining 2 get the water bill. The bill includes a period of 15 days where 4 roommates lived in the apartment. So 15 days of water for 4 people and 49 days for 2 people. How much should each roommate pay? The problem is that 2 people use less water then 4 people so if they just split the bill, the 4 people are paying less than they should. My solution which I'm not sure is correct: Say 1 person uses 1 Dollar worth of water per day, So the 4 roommates used 60 Dollars worth of water, and the 2 roommates used 98 Dollar. So They need to split the bill to 158, The 4 roommates should pay 60 parts of it and the 2 roommates should pay 98 parts of it. But I'm not sure it takes everything into account.
Any help appreciated. Thanks
Say each person uses the same amount of water per day, call it $1$ unit.
Then for the first $15$ days, you used $15$ units per person and $60$ units total. For the next $49$ days, you used $49$ units per person and $98$ units total. All in all, everyone used $158$ units during the entire billing cycle. What's each person's share?