A heat engine under development is expected to transfer heat from reservoir A to reservoir B. Which is a requirement for the two reservoirs
A. the temperature of reservoir A must be equal to the temperature of reservoir B
B. the temperature of reservoir A must be greater than the temperature of reservoir B
C. The internal energy of reservoir A must be greater than the internal energy of reservoir B
D. The internal energy of reservoir A must be equal to the internal energy of reservoir B

x + y = 90 5x – 10y = 90 90 – 10y = 5x 90 + 10y = 5x

step-by-step explanation:

last month maria hiked the 5-mile mountain trail a number of times and she hiked the 10-mile canal trail several times. let x represent the number of times she hiked the 5-mile trail, and let y represent the number of times she hiked the 10-mile trail. if she hiked a total of 90 miles, which equation can be used to find the number of times maria hiked each trail? x + y = 90 5x – 10y = 90 90 – 10y = 5x 90 + 10y = 5x

d

step-by-step explanation:

i used the pitagoras theoreme

the answer is b