Answer:
25 questions
Step-by-step explanation:
At a math competition 2 students can answer 40 questions in 1 hour.
Therefore, 1 student can answer in 1 hour =
= 20 questions
5 students can answer in 1 hour = 20 × 5 = 100 questions
60 minutes = 1 hour
15 minutes = = 0.25 hours
5 students can answer in 0.25 hours = 100 × 0.25
= 25 questions
5 students could answer 25 questions in 15 minutes.
Given:
Total number of marbles in the bag = 150
There are 21 blue marbles for every 4 white marbles.
To find:
The number of blue marbles in the bag.
Solution:
Since, there are 21 blue marbles for every 4 white marbles, therefore the ratio of blue marble to white marbles is 21:4.
Let the number of blue marbles be 21x and white marbles be 4x.
Total number of marbles in the bag = 150
Divide both sides by 25.
Now,
Therefore, the number of blue marbles is 126.