Answer:
It takes 1 seconds for push-ups and 3 seconds for sit-ups for Mei to do exercise.
Step-by-step explanation:
Given:
Let the time taken for push-ups be 'x'.
Let the time taken for sit-ups be 'y'.
Now Given:
17 push-ups and 6 sit-ups, it takes a total of 35 seconds.
So we can say that;

Also Given:
41 seconds to do 20 push-ups and 7 sit-ups.
so we can say that;

Now Multiplying equation 1 by 7 we get;

Now Multiplying equation 2 by 6 we get;

Now Subtracting equation 3 from equation 4 we get;

Now substituting the value of x in equation 1 we get;

Hence It takes 1 seconds for push-ups and 3 seconds for sit-ups for Mei to do exercise.
Answer:
Cheryl is correct.
Step-by-step explanation:
Cheryl solved a problem : 84 ÷ 0.01 = 8,400.
This is absolutely right.
When we divide any whole number with the divisor having decimal, we change the divisor to a whole number before performing the division.
To do this, we multiply both the numbers (divisor and dividend) by the same power of 10, until the divisor is a whole number.
= 
to make divisor a whole number we will again multiply both the numbers by 10.
=
= 8,400
Now answer would be 8400.
Therefore, Cheryl is correct.
Answer:
x>1
Step-by-step explanation:
x + 18 > 19
Subtract 18 from each side
x + 18-18 > 19-18
x>1