Question

Michelle is 7 years older than her sister Joan, and Joan is 3 years younger than their brother Ryan. If the sum of their ages is 64, how old is Joan?

Answer 1

Joan is 18 years old.

Step-by-step explanation:

Let's denote Joan's age as J, Ryan's age as R, and Michelle's age as M.

Based on the given information, we can form the following equations:

• M = J + 7 (Michelle is 7 years older than Joan)
• J = R - 3 (Joan is 3 years younger than Ryan)
• M + J + R = 64 (the sum of their ages is 64)

Substituting the second equation into the first equation, we get: M = (R - 3) + 7 = R + 4.

Substituting the expressions for M and J in the third equation, we have: (R + 4) + (R - 3) + R = 64. Simplifying this equation, we get: 3R + 1 = 64.

Solving for R, we subtract 1 from both sides: 3R = 63. Dividing both sides by 3, we find: R = 21.

Now we can substitute R = 21 into J = R - 3 to find Joan's age: J = 21 - 3 = 18.

Therefore, Joan is 18 years old.

Answer 2

Answer: Joan is 18 years old.

Step-by-step explanation:

Let x be the present age of Ryan.

Then age of Joan = x-3.

Age of Michelle = (x-3)+7=x-3+7=x+4

Also, the of their ages is 64, then we have the following equations ;_

`x+x-3+x+4=64\\\\\Rightarrow\ 3x+1=64\\\\\Rightarrow\ 3x=64-1\\\\\Rightarrow\ x=(63)/(3)=21`

Now, The age of Joan = x-3= 21-3=18

Hence, Joan is 18 years old.