The ratio of pop songs to rock songs you download is 5:4, and 40 are pop songs. You want to find out how many rock songs there are.
First, add the ratios together: 5+4=9. This means that 9 will be your denominator, so 5/9 songs are pop and 4/9 songs are rock.
Now you know that pop songs account for 5/9 of the songs, this means that 40 is 5/9 of the total songs.
To find out how much 4/9 is, you need to divide 40 by 5 to get 1/9 and times that number by 4 to get 4/9:
40÷5=8×4=32 songs are rock songs

7 0

3 years ago

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A pharmacist has 40% and 60iodine solutions on hand. How many liters of each iodine solutions will be required to produce 4 lite

Schach [20]

A pharmacist has 40% and 80% of iodine solutions on hand. How many liters of each iodine solution will be required to produce 4 liters of a 50% iodine mixture?

Let x = liters of 40% iodine

then

4-x = liters of 80% iodine

Using algebra:

.40x + .80(4-x) = .50(4)

.40x + 3.20-.80x = 2

3.20-.40x = 2

x = 4 liters (40% iodine)

80% iodine:

4-x = 4-4 = 0 liters needed (80% iodine)

4 0

3 years ago