A teacher records the marks scored by 30 students in an English test. Mark Frequency

1−5 1

6−10 4

11−15 6

16−20 6

21−25 8
26−30 5

a Calculate an estimate of the mean score.

Give your answer to 1 decimal place.

+25 = x

step-by-step explanation:

here x is the hypotenuse of a right triangle whose legs are 7 and 24.   by the pythagorean theorem, 7² + 24² must equal x²:

x² = 49 + 576 = 625.   thus, x = +√625 = +25 = x

is this part of a question or something

step-by-step explanation:

to find if any function is an inverse of the other, put the first equation in as x in the next one. then simplify and solve. if at the end you get the statement y = x, then it is an inverse. if you get anything else, it is not.