9x-30 I’m pretty sure!
We are finding the difference, which means subtract! Nine times a number would be 9x and since it’s difference you would subtract it by 30.
Answer:
The ratio between won and lost is 
Step-by-step explanation:
<u><em>The question in English is</em></u>
A table tennis team won 21 games and lost 12 games, what is the ratio between won and lost?
Let
x ------> the number of games won
y -----> the number of games lost
we have
we know that
To find the ratio divide the number of games won by the number of games lost
so
substitute the values
Simplify
<span>Length of outer track = sum of length of 10 pieces = circumference of the outer circle
if R is the Radius of outer circle then...
Circumference of the outer track = 2pi*R
Similarly the circumference of the inner track (with radius r) = 2pi*r
length of each outer piece is 3.4 inch more than length of inner piece
So total outer length is 10*3.4 =34 inches more than the inner length.
=> Outer Circumference - Inner Circumference = 34 inches
=> 2pi*R - 2pi*r = 34
=> 2pi(R -r) = 34
=> R-r = 34/2pi = 5.41 inches
=> R-r = Width of the track = 5.41 inches</span>
