Mathematics for IGCSE & O level - Ratio And Proportion (Section 1 - No. 49)
The ratio of red to blue marbles in a bag is 2:5. There are 10 red marbles. How many total marbles are there?
25
30
35
49
Обяснение
2:5. 10 marbles mean ratio *5, so 10 red, 25 blue marbles. total is 35.