78, because you have to do the inverse operation so 80/2= 40 then 40-1= 39 and 39*3 = 78
I'm not 100% sur what it is asking but I think the expression would be
15 min. * 10 = min. till the tank is full
Answer:
30
Step-by-step explanation:
To calculate the area of a triangle you will do it like a square or rectangle but you will divide your answer by 2. So...
10 * 6 = 60
60 / 2 = 30
Answer: 0.6 in 10 % ; 0.4 in 15 %
Step-by-step explanation:
1. (x*10%) + (y*15%)/ x+y=12%
2. x+y = 1 x= 1-y
(0.1x + 0.15y/ x+y= 12/100) * 100
(10x + 15y/x+y = 12)*(x+y)
10x+15y= 12x + 12y
-2x=-3y
2x = 3y 2(1 - y)= 3y
2-2y=3y 2= 5y
y= 0.4
x= 0.6
