You want 
. We can go about this by casework. WLOG x=9, we have 8 digits: 1-8. With x=8 we have 2-9, but we already counted 8 and we already considered the 9 case, so we have 2-7 actually, which will give us 6 numbers. With x=7, with the same logic we are only looking for the numbers 3-6 which there are 4 of. With x=6, you are looking for the numbers 4-5 which are 2. With x=5 run out of numbers to pick. The numbers are indistinguishable and it does not matter whether we use x or y so we just have to ad up the cases we already have to get: 20.
80 might be the answer you are looking for
Answer:
1381 minutes
Step-by-step explanation:
Write it as an equation.
0.05x+22=91.05
Where x is the minutes used.
Solve.
0.05x=69.05
5x=6905
x=1381
Your picture shows the first step: use the distributive property to eliminate parentheses.
5*7 -5*x = 2*x -3
Now, you have an equation with a constant and an x-term on each side. I like to pick the x-term with the smallest (most-negative) coefficient and add its opposite to the equation.
Adding 5x, we have
35 = 7x -3
Adding 3 will get the x-term on one side and the constant on the other
38 = 7x
Now, we divide by the coefficient of x
38/7 = x = 5 3/7
This is the correct answer, even though it is not an integer.
_____
Check
5(7 -(5 3/7)) = 2(5 3/7) -3 . . . . substitute for x in the original equation
5(1 4/7) = 10 6/7 -3 . . . . . . . . . evaluate the parentheses on the left, do the multiplication on the right
5 20/7 = 7 6/7 . . . . . . . . . . . . do the multiplicaton on the left, the subtraction on the right
5 +2 6/7 = 7 6/7 . . . . . . . . . . . rewrite 20/7, realize 5+2=7. true
