At joe′s café, one cup of coffee and three doughnuts cost $3.40, and two cups of coffee and two doughnuts cost $4.00
what is the cost of one doughnut? cents.
what is the cost of one cup of coffee? dollars.

Element x decays radioactively with a half life of 8 minutes. if there are 450 grams of element x, how long, to the nearest tenth of a minute, would it take the element to decay to 37 grams?

Aswimming pool has an input pump for filling the pool and an output pump for emptying the pool. the input pump can fill the pool in 3 hours, and the output pump can drain the pool in 5 hours. as you go to bed, the pool is full, but a neighbor’s kid turns on the output pump. at midnight, you awake to find the pool half empty. immediately, you turn on the input pump, but you are sleepy and forget to turn off the output pump. at what time will the pool become full?

2pointswhich of the following appear in the diagram below? check all that apply.d a. zcdeов. сеo c. aéo d. zdce