A bowl contains 675 sweets which are coloured either red, blue or green.

The ratio of red sweets to blue sweets is 3 : 7
The ratio of blue sweets to green sweets is 4 : 5
Calculate the number of blue sweets that are in the bowl.

please provide an explanation; i would like to understand for future ref :)

4 answers

The ratio of red sweets to blue sweets is 3 : 7, which means that for every 3 red sweets there are 7 blue sweets. Since we know that there are 675 sweets in total, we can calculate the number of blue sweets by multiplying 675 by 7/3. This gives us 315 blue sweets.
that is incorrect
nevermind! i got the answer: 252
b = (4/5) g , so g = (5/4) b
r = (3/7) b
so
(3/7) b + (5/4) b + b = 675
(12/28) b + (35/28) b + (28/28) b = 675
(75/28) b = 675
b = 252 , sure enough :)