Page 70 - Mathematics

The ratio can be written in Writing in fraction form gives,
rice 2 3 green 5 y
fraction as = = ==
corn 5 x blue 4 20 (i)
2 3
Thus, = red 3 x
5 x blue == (ii)
4 20
Cross multiplication gives, From equation (i), it follows that,
2x = 35× 5 y
35× =
x = 4 20
2
Tanzania Institute of Education
7.5= Cross multiplication gives,
Therefore, the special cereal 4y = 5 20×
mixture contains 7.5 kilograms of 5 20×
corn. y = 4
25=
Example 4.8 From equation (ii), it follows that,

3
A clothing shop sells t-shirts which = x
are in three colours: red, blue, and 4 20
green. The colours are in the ratio Cross multiplication gives,
of 3 to 4 to 5, respectively. If the 4x = 3 20×
shop has 20 blue t-shirts, how many
t-shirts are there in the shop? x = 3 20×
4
Solution 15=
Let x be the number of red t-shirts Thus, the total number of t-shirts

and y be the number of green is 15 + 20 + 25 = 60.
t-shirts.
Writing the items in ratios gives, Therefore, the clothing shop has

: 20 and
green: blue 5: 4= = = x y : 20 60 t-shirts.
Mathematics Form One
red: blue 3: 4=

64

25/10/2024 09:51:19
Mathematics form 1.indd 64
Mathematics form 1.indd 64 25/10/2024 09:51:19