0.78 per pound is unit rate
Since 5lbs is $3.90, 0.78 is the cost of one pound.
3.90 divided by 5 is 0.78
Philip and Barbara are 8 meters apart because 5+3=8 so it will make 8 meters

=

Multiply both sides by 15
6 =

Multiply both sides by c
6c = 30 Divide both sides by 6
c = 5
So 36% of x is 18
percent is parts out of 100
36%=36/100=0.36
'of' can be translated as muitiply
0.36 times x=18
divide both sdies by .36
x=50
the number is 50