Step-by-step explanation:
Let's say the two digit number is 10x + y, where x is the first digit and y is the second digit.
The sum of the digits is 8:
x + y = 8
If 8 is subtracted from the number, the digits switch place.
10x + y − 8 = 10y + x
Simplify the second equation:
9x − 8 = 9y
Substitute from the first equation.
y = 8 − x
9x − 8 = 9 (8 − x)
9x − 8 = 72 − 9x
18x = 80
x = 4.444
There's a problem. x isn't an integer. Are you sure you copied the problem correctly? Perhaps you meant if 18 is subtracted from the number, the digits switch place.
9x − 18 = 9 (8 − x)
9x − 18 = 72 − 9x
18x = 90
x = 5
y = 8 − x
y = 3
So the number is 53.
Answer:
The time now is 7 pm
Step-by-step explanation:
Suppose that now is the time T.
We know that:
"if time is four hours from now, the time left till midnight would be a quarter that if it is one hour from now".
Then:
if we define midnight as 12, and we assume that T is in the pm range.
Then the "time left till midnigth, assuming that the time is four hours from now" will be written as (12 - (T + 4))
With this in mind, we can write the problem as:
12 - (T + 4) = (1/4)*( 12 - (T + 1))
Now we can solve this for T.
12 - T - 4 = (1/4)*(12 - T - 1)
8 - T = (1/4)*(11 - T)
4*(8 - T) = 11 - T
32 - 4*T = 11 - T
32 - 11 = -T + 4*T
21 = 3*T
21/3 = T
7 = T
Then T = 7 pm
The time now is 7 pm
Answer:
x > -15, you are welcome we all need help
Answer:
x = 60
Step-by-step explanation:
The tip of the triangle's angle is 100 (b/c 180-80)
x + 100 + 20 = 180
x + 120 = 180
x = 60
Let's write some equations.
Mingwei's distance from Town A after
hours from 8:00 is
.
Ali's distance from Town B after
hours is
, since he doesn't start walking for 40 minutes.
When Mingwei's distance is twice Ali's, they've met up (since their distance from Town A is twice their distance from Town B).
So, this gives
, so
, so
, so the time is 10:40.
After
hours, Mingwei has traveled
kilometers while Ali has traveled sixty, so the distance between the towns is
kilometers.
