Set up a proportion here as the height over the shadow of the adult = to the height over the shadow of the baby. so you have 12/4.8 = height/2. cross multiply to get 12*2=4.8 times height, which is 24 = 4.8*height. divide both sides by 4.8 to get height = 5 feet
4x-3y=17......(1)
5x+4y=60......(2)
Multiply equation (1) by 4 and equation (2) by 3:-
16x - 12y = 68
15x + 12y = 180
Adding these 2 equations:_
31x = 248
x = 248/31 = 8
Now substitute x = 8 in equation (1):-
4(8) - 3y = 17
32-3y = 17
-3y = -15
y = -15/-3 = 5
So solution is x=8,y=5
For your first one it’s definitely 94$
It was $930.
To over check, multiply it by 20% , you will get $186.
Hope this helps !
What do you not understand