ACT math help

Test Preparation ACT Preparation
1

Can someone explain these

Jill and matt began at the same point but ran around the track in opposite directions. Jill ran at a constant speed that was 2 meters faster than Matt’s constant speed. jill passed Matt for the first time in 40 seconds. Jill ran at a constant rate of how many meters per second? (400 meter long track, they run 10 laps daily)
A4
B5
C6
D7
E10

Correct answer is C

if n!/(n-2)! = 30, then (n-1)!=
A15
B24
C60
D120 (correct)
E720

I got this one right but I was wondering why it couldn’t be another answer as well?
what forms f(gx))= square root of 2X^2+3

f(x) = square root of x, g(x) = 2x^2+2

and this was wrong but why? f(x)= square root of x^2+3, g(x)= 2X

2
  1. Jill speed= x+2, Matt = x (x+x+2)(40 seconds) = 400 meter long track 80x+80=400 x=4, Jill=6
  2. n!/(n-2)! = n(n-1) = 30; n=6; 5!=120
  3. (2x)^2 = 4x^2, not 2x^2

cmon upenngal-if u wanna make it dere u gotta know these (not supposed to be hard questions)

3

it was mainly to grab people’s attention lol. generally i am pretty decent at the math section but it always seems to be the most basic questions that stump me.

4

I honestly don’t get #2 or 3, so they weren’t easy to me.