Question 271038
{{{f}}} = Fred's age now
{{{b}}} = Barney's age now
{{{f - 5}}} = Fred's age 5 years ago
{{{b - 5}}} = Barney's age 5 years ago
given:
(1) {{{f = b + 4}}}
(2) {{{(f - 5) + (b - 5) = 48}}}
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Substitute (1) in (2)
(2) {{{(b + 4 - 5) + (b - 5) = 48}}}
{{{b + b - 6 = 48}}}
{{{2b = 54}}}
{{{b = 27}}}
from (1),
{{{f = b + 4}}}
{{{f = 27 + 4}}}
{{{f = 31}}}
barney is 27 and Fred is 31
check:
(2) {{{(f - 5) + (b - 5) = 48}}}
(2) {{{31 - 5 + 27 - 5 = 48}}}
(2) {{{26 + 22 = 48}}}
{{{48 = 48}}}
OK