75x + 90(15-x)=88(15)
75x+1350-90x = 1320
-15x + 1350 = 1320
-15x= -30
x=2
the amount of 75 octane is 2 gallons
the amount of 90 octane is 13 gallons
Hope this helps.
Good question let me see if I can figure it out
<u>x = 9</u>
Step-by-step explanation:
mean = 5+7+7+x /4 = 7
19+x / 4 = 7
19+x = 28
x = 9
He bought 4 cards for $4 so that's 16 he put 20 in each that's 80 and 70 x 4 is 1,400 so all of that in total would be 1,436, correct me if I'm wrong, and if you're too lazy to read than, the answer is 1,436