So, there will be 40 green cars. if we want the ratio to be 1:3, we will need there to b three times as many silver cars as green cars: 40*3=120.
we already have 20 silver, so we need to add 120-20, that is 100 silver cars!
Answer:

Step-by-step explanation:
To evaluate
from the following expression:

Taking 


∴ 
please edit your question man
Answer:
16 problems.
Step-by-step explanation:
100% divided by 20 questions.
100/20 is equal to 5, therefore each question is worth 5 points.
Grade of 80% divided by points per question.
80/5 is 16 so the student answered 16 questions correctly.