Answer: 64 yrs
Explanation:
To find Chris' age, we can follow these steps:
Step 1: Determine Bobby's age.
Given that the ratio of Alan's age to Bobby's age is 7:8, and we know that Alan is 70, we can set up the following equation:
Alan's age / Bobby's age = 7/8
70 / Bobby's age = 7/8
Cross-multiplying, we have:
8 * 70 = 7 * Bobby's age
560 = 7 * Bobby's age
Divide both sides by 7:
Bobby's age = 560 / 7
Bobby's age = 80
So, Bobby is 80 years old.
Step 2: Determine Chris' age.
Given that the ratio of Bobby's age to Chris' age is 5:4, we can set up the following equation:
Bobby's age / Chris' age = 5/4
Substituting Bobby's age as 80, we have:
80 / Chris' age = 5/4
Cross-multiplying, we get:
4 * 80 = 5 * Chris' age
320 = 5 * Chris' age
Divide both sides by 5:
Chris' age = 320 / 5
Chris' age = 64
Therefore, Chris is 64 years old.