Question 547507
I will put all the data in terms of months
Let {{{p}}} = puppy's current age in months
Let {{{j}}} = Jesse's age in months
given:
(1) {{{ p = ( 1/2 )*( j/12 ) }}}
(2) {{{ p + (5*12) = 2*(j/12) + 5 }}}
--------------------------
This is 2 equations and 2 unknowns, 
so it's solvable
(1) {{{ p = j/24 }}}
(2) {{{ 12p + 720 = 2j + 60 }}}
(2) {{{ 6p + 360 = j + 30 }}}
Substitute (1) into (2)
(2) {{{6*(j/24) + 360 = j + 30 }}}
(2) {{{ j/4 + 360 = j + 30 }}}
(2) {{{ j - j/4 = 360 - 30 }}}
(2) {{{ (3/4)*j = 330 }}}
(2) {{{ j = (4/3)*330 }}}
(2) {{{ j = 440 }}}
and
(1) {{{ p = j/24 }}}
(1) {{{ p = 440/24 }}}
(1) {{{ p = 18.333 }}}
The puppy's age is 18 months and 10 days
---------------------------------
check:
Jesse's age in years is {{{ 440/12 = 36.666 }}}
The puppy's age in months is 1/2 Jesse's age in years
---------------
In 5 years, the puppy's age in months will be
{{{ 18.333 + 60 = 78.333 }}}
Twice Jesse's age in years in 5 years will be
{{{ 2*36.666 = 73.333 }}}
OK