Answer: 348 students do not own a cell phone.
Step-by-step explanation:
12 out of 15 = 80%
80% of 435 = 348
4x + 10 = 2x + 20
4x - 2x = 20 - 10
2x = 10
x = 5
x − y = 0 = difference
x + y = 4 = sum
Can be solved by the sum and difference rule (most of the time without pen and paper)
x=(sum+difference)/2=0+4/2=2
y=(sum-difference)/2=(4-0)/2=2
For sum u add and for difference you subtract
So, we have the information:
Save $10 first month
$5 the next months
X = amount of months
Cost = 175
So, it will take 7 months.
10+15+20+25+30+35+40 = 175
