To do that you'll need the mean and standard deviation of all the scores. Can you provide this info?
For example: Supposing that the mean of these scores were 52 and the standard deviation 3. You'd need to find the "z-score" of 57 in this case.
57 - 52
It is z = ------------ , or z = 5/3, or z = 1.67.
3
Find the area to the left of z = 1.67. Multiply that area by 100% to find the percentile rank of the score 57.
y = 8
using the ' gradient formula' m = (y₂ - y₁)/(x₂ - x₁)
with (x₁, y₁) = (3, 3), (x₂, y₂) = (- 5, y) and m = - 
(y - 3)/( - 5 - 3) = - 
(y - 3)/(-8) = - 
multiply both sides by - 8 to eliminate fractions
y - 3 = 5
add 3 to both sides
y = 5 + 3 =8
Let's the name the first number x and the consecutive number x + 1. The sum of both of these numbers equals to 53.
We now have our equation:
x + x + 1 = 53
Now solve for x.
x + x + 1 = 53
2x + 1 = 53 <-- Combine like terms
2x = 52 <-- Subtract 1 from each side
x = 26
So, the first number is 26 and the second number is 27.
Answer: The number of letters that must be engraved for the costs to be the same is 125.
Step-by-step explanation:
Since we have given that

We need to find the number of letters.

Hence, the number of letters that must be engraved for the costs to be the same is 125.
R equals approximately 4/5