
Step-by-step explanation:

3:4 = G:B
1:5 = Mr. Smith's class: 7th Grade
2:7= 7th: Middle school
12 girls = 3 units
1 unit = 12/3= 4
Boys = 4x4= 16
<em>Whole class = 28 students</em>
Class : Grade = 1:5 <em> 7 = number of units in Mr. Smith's class</em>
28 = 1 unit
5 units= 28x5= 140 <em>There are 140 kids in the grade</em>
140 = 2 units
1 unit = 140/2= 70
70x7=490
<u><em>There are 490 students in the whole grade</em></u>
3(2x+2)=3x-15
mutiply the bracket by 3
(3)(2x)(3)(2)= 6x+6
6x+6= 3x-15
move 3x to the other side
sign changes from +3x to -3x
6x-3x+6= 3x-3x-15
6x-3x+6= -15
3x+6= -15
move +6 to the other side
sign changes from +6 to -6
3x+6-6= -15-6
3x= -21
divide by 3 for both sides
3x/3= -21/3
x= -7
Answer: x= -7
Answer: $150
Step-by-step explanation:
Becky spends 3/5 of her Money and is left with 2/5 of her money.
Hence 2 parts = $60
And 5 parts = $150
Becky has $150 at first.
Answer: z= 1.3
Divide both side by 4.5