$27 x 18 students = 486 actual cost.
$30 x 10 students = 300 estimated total cost using compatible numbers.
$20 x 20 students = 400 estimated total cost using compatible numbers. (better option because it is nearer to the actual cost)
Compatible numbers are numbers that can easily be multiplied or divided using mental computation.
Compatible number for 27 and 18 can be: 30 and 20 OR 20 and 20 OR 30 and 10 OR 20 and 10.
However, there is a rule in multiplying the compatible numbers, when one number is increased the other number must be decreased.
So 27 can be increased to 30; while 18 can be decreased to 10 to get a product of 300.
27 can be decreased to 20; while 18 can be increased to 20 to get a product of 400.
We will have the following:

So, the original quantity was approximately $183 293.75.
200cm which has been rounded up to to the nearest cm meaning it could be 199.5cm. Then times it by 32.
199.5 x 32 = 6384cm
Answer:
20
Step-by-step explanation:
we see here that angle RPN is 180 degrees. SPM is 90 degrees so
angle RPS + angle SPM + angle MPN = 180 degrees
(4y - 10) + 90 + y = 180
(4y - 10) + y = 90
5y - 10 = 90
5y = 100
y = 20