SOLUTION: Mary (m) is 4 years older than Rico (r). Ten years ago Mary was 3 times as old as Rico was then. a) how old are they now? b) determine if answer is correct by checking that it sa
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Question 309626: Mary (m) is 4 years older than Rico (r). Ten years ago Mary was 3 times as old as Rico was then. a) how old are they now? b) determine if answer is correct by checking that it satisfies the conditions of the problem
I've got r = 4 = m and have to subtract 10 years from both and multiply both by 3?
3(r-10) = m -10
3r - 30 = m -10
m = 3r - 20
r + 4 = 3r -
4 + r = -20 + 3r (subtract 3r from both sides)
4 + -2r = -20 (subtract 4 from both sides)
-2r = -24 (divide both by -2) gives the solution of 12?
so if I was solving for r, then that is Rico's age 10 years ago?? He would be 22 now and if 4 years older, Mary would be 26? This can't be right if 10 years ago she was 3 times his age.
You can put this solution on YOUR website! Mary (m) is 4 years older than Rico (r).
Write an equation for this statement first:
m = r+4
Ten years ago Mary was 3 times as old as Rico was then.
a) how old are they now?
I've got r = 4 = m?????? and
have to subtract 10 years from both and multiply both by 3?
3(r-10) = m - 10
3r - 30 = m -10
Correct up to here, now
3r = m - 10 + 30
3r = m + 20
Replace m with (r+4)
3r = (r+4) + 20
3r - r = 24
2r = 24
r =
r = 12 yrs is Rico's present age
and we know
m = r + 4
m = 12 + 4
m = 16 yrs is Mary's present age
:
b) determine if answer is correct by checking that it satisfies the conditions of the problem
Check solution in the statement:
" Ten years ago Mary was 3 times as old as Rico was then. "
16 - 10 = 3(12 - 10)
6 = 3(2); confirms the solutions
:
:
Did this help straighten things out for you?
