Answer:
The rate of the second car is 30 miles/hour
Step-by-step explanation:
The Given formula is:
4(r + 15) + 4r = 300, where r is the rate for the second car
Let us solve the equation to find r
→ Multiply 4 by (r + 15) first
∵ 4(r + 15) = 4(r) + 4(15) = 4r + 60
→ Substitute it in the equation above
∴ 4r + 60 + 4r = 300
→ Add the like terms in the left side
∵ (4r + 4r) + 60 = 300
∴ 8r + 60 = 300
→ Subtract 60 from both sides
∴ 8r + 60 - 60 = 300 - 60
∴ 8r = 240
→ Divide both sides by 8
∴
∴ r = 30
∴ The rate of the second car is 30 miles/hour