Answer:
Step-by-step explanation:
Suzette ran and biked for a total of 50 miles in 4 hours. Her average running speed was 5 mph and her average biking speed was 15 mph.
Let x = total hours Suzette ran.
Let y= total hours Suzette biked.
Distance = speed × time
Distance covered in running for x hours at a speed of 5 miles per hour = 5×x = 5x miles
Distance covered in biking for y hours at a speed of 15 miles per hour = 15×y = 15y miles
Total distance covered is 50 miles. This means
5x + 15y = 50 - - - - - - - - 1
If the total time spent is 4 hours, that means
x + y = 4
Substituting x = 4 - y into equation 1,
It becomes
5(4 - y) + 15y = 50
20 - 5y + 15y = 50
- 5y + 15y = 50 - 20
10y = 30
y = 30/10 = 3
x = 4 - y = 4 - 3
x = 1
a) Suzette ran for 1 hour
b) Suzette biked for 3 hours
