CPhill

Roman Numeral divsion....we don't get many of those!!!

XC = 90   

X = 10

90/10  = 9    or IX, if you're going "old school"

P. S.  .....let me know if you find a Roman "Zero"   {it's an old forum joke}

Yep...correct !!!

Very good  !!!

For the second....let the number of campers = N   and the total tents = T   so we have

T =  ceiling(N/3) + 1  

The "ceiling" is defined as  ..   the least integer that is greater than or equal to (N/3)

Thus, if we had 21 campers  ...  ceiling(N/3) = ceiling(21/3) = ceiling(7) = 7

However, if we had 22 campers ... ceiling(22/3) = ceiling(7 + 1/3) = 8

The reason for using this is that we need an "extra" tent  for any "fractional"  campers

For the first one, let the total cost = C  and the time worked =T

So we have

C = 40T + 50   

{The "40T" is known as the "variable" cost and the "50" is the "fixed" cost...}

Yep....that's it !!!

This looks difficult...but it's not.....

Notice  that  400! / 398!  =  (400 x 399 x 398 x 397.......) / (398 x 397 x 396 x 395...)

All all the terms on the "top" cancel with all the terms on the "bottom" except 400 x 399

Can you take it from here??

I could give you the answer....but it is more important that you understand this fully...here is an excellent ( and an easy-to-understand) resource.....

The area of the rectangle = 12mm X 18mm = 216mm^2

And the area os a square = side^2

Thus

side^2  = 216    take the sq root of both sides

side = sqrt 216  = sqrt (36 * 6) = 6*sqrt(6)   ......and that's in mm

Just put  "sqrt 53" into the calculator.....what is the "whole" number part of the answer???....what two integers does this whole number lie between???

Alternative "hint"

7^2  = 49

8^2 = 64

Does 53 lie between these two numbers??

Just put (3.54 x 3.68) into the calculator and hit '='......magic will occur and your answer will be in m^2