Answer
Find out the ratio represented the number of yellow balls to red balls .
To proof
Let us assume that the number of yellow balls be x.
As given
There are 20 balls in a bag.
Ten of the balls are red, 4 are green, and the rest are yellow.
than the equation becomes
x + 10 + 4 = 20
x = 20 - 14
x = 6
therefore the number of yellow balls be 6 .
Now find out the ratio between the the number of yellow balls to red balls .
the number of yellow balls be 6 .
the number of red balls be 10 .
\(\frac{Number\ of\ yellow\ balls}{Number\ of\ red\ balls} = \frac{6}{10}\)
solving
\(\frac{Number\ of\ yellow\ balls}{Number\ of\ red\ balls} = \frac{3}{5}\)
Therefore the ratio of the the number of yellow balls to red balls is 3 :5 .
Option (d) is correct .
Hence proved
