Answer:
4 (20) + 6(6) = 120
4(20) + 4 (6) = 100
Explanation:
Hi, to answer this question we have to write a system of equations with the information given:
Build time (hours) = 4c + 6a = 120
Test time (hours) = 4c + 4 a = 100
Where c represents the number of child bikes and a represents adult bikes.
So, for 20 child bikes and 6 adult bikes:
4 (20) + 6(6) = 120
4(20) + 4 (6) = 100
Feel free to ask for more if needed or if you did not understand something.