Answer: This is what Khan Academy said the answer was
Answer:
There it gose
Step-by-step explanation:
B = hours babysitting
m = hours giving music lessons
so... whatever "b" and "m" are, their sum for that week was 18
thus
b + m = 18
now, money wise, she makes $5 for "b" and that is, she made 5*b or 5b that week
for "m", she makes $12, so for that week she made 12*m or 12m
whatever "b" and "m" are
thus
5b + 12m = 139
now

solve for "b", to see how many hours she spent babysitting
So since the kitchens long is wide x 2 if you add the 2 longs it makes a wide so you end up with 3 wides technically. So you divide 84 by 3 and u get 28 so make your 2 wides 28. Then u divide 28 by 2 to get 14 so your longs are 14 and your wides are 28 if u add it all together it’s 84.
3 digits are behind the decimal
2.54*0.2= 0.508
So it would be three
Hopefully this helps...