Question

A bag contains 100 marbles which are red, green, and blue. suppose a student randomly selects a marble without looking, record's the color,and then places the marble back in the bag the student has recorded 7 red marbles, 2 green marbles and 11 blue marbles. predict how many green marbles are in the bag​

Answer 1

Answer: 10 marbles

Explanation:

First, arrange all the numbers of marbles that the student picked in a ratio

red:green:blue

7:2:11

When adding all the coloured marbles that the student picked together, you get 20 marbles or "parts" as you would usually say in ratio.

Then, it would be helpful to rewrite the ratios as fractions, with 20 as the denominator:

`(7)/(20):(2)/(20):(11)/(20)`

However, the bag contains 100 marbles so we should have 100 as the denominator instead of 20. 20 is a fifth of 100, so in this case, we would multiply everything (the numerator and the denominator) by 5:

`(7*5)/(20*5) :(2*5)/(20*5) :(11*5)/(20*5)`

`(35)/(100):(10)/(100):(55)/(100)`

Therefore, you could predict you would get 35 red marbles, 10 green marbles, and 55 blue marbles.