Answer:
see below
Step-by-step explanation:
butterfly = x minutes
breast = y minutes
total is 50 minutes
breast stroke = butterfly +20
Part A
x+y = 50
y = x+20
Part B
Substitute the second equation into the first
x+ (x+20) = 50
2x+20 = 50
2x+20-20 = 50-20
2x = 30
2x/2 = 30/2
x = 15
y = x+20
y = 20+15
y = 35 minutes
35 minutes on the breast stroke
Part C
45 minutes on the butterfly is not reasonable
We only have a total of 50 minutes
50-45 = 5
But he spend more time on the breast stroke ( 20 minutes more), but if he spend 45 minutes on the butterfly, he would have to spend less on the breast stroke.
Speed is the ditance traveled by a certain object given a certain time span. To solve this problem we need to divide the distance by the time given. Before that, the problem asked us to get the speed in terms of miles per minute and we are given a distance of 3 kilometer. We have to convert this to miles. 3km(0.6miles/km) = 1.8 miles. The speed is then 1.8/20 = 0.09mi/min.
