80% of 20 is 80/100 x 20 = 16
So, kelly has used 16 stamps, and has 4 left
Answer:
12 years old.
Step-by-step explanation:
1) 2x+x=18
2) Now solve 2x+x=18
Add alike terms
3x=18
Now divide both sides by 3 (3x/3 and 18/3)
x=6
So Hannah is 6 years old. Her sister must be 12.
Answer:
z = -5
Step-by-step explanation:
3(0.7z + 2.8) = 7(1.5z + 7.2)
2.1z + 8.4 = 10.5z + 50.4
2.1z - 10.5z = 50.4 - 8.4
-8.4z = 42
z = 42/(-8.4)
z = -5
It’s the first option.
5.85/6.5= 0.90