I am currently dong the same thing, if you go to symbolab.com then im pretty sure you'll be helped. ;)
Answer:
I think its 2 good luck
Step-by-step explanation:
1 hour each day is used for test
so 8-1=7 used per day
so commercial is 1 in the 4:2:1 so
4+2+1=7
ok, so 7 units, 7 hours
4 hour for private
2 hour for research
1 hour of commerical
4*5=20=private
2*15=30=research
1*4=40=commercial
20+30+40=90
percent from commercial
40/90=0.44444444444≈44.44% about 44%
The answer is 315 as the formula is : a+b/2•h.
