Answer:
53
Step-by-step explanation:
Given: The sum of two digit number is 8
Reversing the digit will get us number 18 less than the original.
Lets take x as tenth digit of our number and y as unit digit of our number.
As given sum of digit is 8
∴ 
∴
- equation 1
We also know that reversing the digit will get us number 18 less than the original.
∴ 
Now, lets put the value of y from equation 1
⇒ 
⇒ 
⇒ 
∴ 
Next, substituting the value of x in equation 1

⇒ 
∴ 
∴ The original number is 53, sum of the digit is 8 and if we reverse the digit of the number, we get 35, which is 18 less than the original number.
Answer:
B: 7.5
Step-by-step explanation:
Use the formula a²+b²=c² to calculate. a=x b=13 c=15. Simply plug in the numbers to the coresponding letters
a²+13²=15²
a²+169 = 225
-169 -169
__________
a²= -56
a = 7.5
3-3 0
——- = —— = zero
-9-9. -18
Initially started 20 feet from the ground .
Went uphill 83 feet.
So: 20 + 83 = 103. The coaster is 103 ft above at this point.
Went down 42 feet
So: 103 - 42 = 61.
Went up 128 feet
So: 61 + 128 = 189
Finally, went down 90 feet
So: 189 - 90 = 99
99 ft above ground.