In the year 1980, Rick was twice as old as Nancy who was twice as old as Michael. In the year 1992 Ric, Nancy, and Michael ages added up to 78 years. How old was Ric in 1980?
Age in 1980:
m + 12 + 2m + 12 + 4m + 12 = 78
Solve for m in the equation m + 12 + 2m + 12 + 4m + 12 = 78
Step 1: Group the m terms on the left hand side:
(1 + 2 + 4)m = 7m
Step 2: Group the constant terms on the left hand side:
12 + 12 + 12 = 36
Step 3: Form modified equation
7m + 36 = + 78
Step 4: Group constants:
We need to group our constants 36 and 78. To do that, we subtract 36 from both sides
7m + 36 - 36 = 78 - 36
Step 5: Cancel 36 on the left side:
7m = 42
Step 6: Divide each side of the equation by 7
7m/7 = 42/7
m = 6
Rick's age = 6 * 4 = 24
Source
Age in 1980:
- Let Michael's age be m
- Nancy's age is 2m
- Rick's age is 2 * 2m = 4m
- Michael's age = m + 12
- Nancy's age is 2m + 12
- Rick's age is 2 * 2m = 4m + 12
m + 12 + 2m + 12 + 4m + 12 = 78
Solve for m in the equation m + 12 + 2m + 12 + 4m + 12 = 78
Step 1: Group the m terms on the left hand side:
(1 + 2 + 4)m = 7m
Step 2: Group the constant terms on the left hand side:
12 + 12 + 12 = 36
Step 3: Form modified equation
7m + 36 = + 78
Step 4: Group constants:
We need to group our constants 36 and 78. To do that, we subtract 36 from both sides
7m + 36 - 36 = 78 - 36
Step 5: Cancel 36 on the left side:
7m = 42
Step 6: Divide each side of the equation by 7
7m/7 = 42/7
m = 6
Rick's age = 6 * 4 = 24
Source