EXERCISE 6.3
Question 1
Cost of 6 bowls = Rs 90
Then Cost of 10 Such bowls = ?
Let cost of 10 bowls = Rs x
1.e $\begin{aligned} \frac{x}{90} &=\frac{10}{6} \\ x &=\frac{10 \times 90}{ 6} \\ x &=₹ 150 \end{aligned}$
∴ Cost of 10 Such bowls = Rs 150
Question 2
With the cost of Rs 15 ,we bought = 10 pencils
Then with the cost of Rs 72 ,we bought =? Pencils
Let it be = x pencils
i.e $\frac{x}{10}=\frac{72}{15}$
$x=\frac{32 \times 10}{15}$
$x=\frac{720}{15}$
$x=48$ pencils
Question 3
Given 400 grams Cake costs Rs 80
Then 1.5 kg Cake Cost = ?
Let the cost be Rs x
i.e
$\begin{aligned} \frac{x}{80} &=\frac{1.5 \mathrm{k}{g}}{400} \\ \frac{x}{80} &=\frac{1.5 \times 1000}{400} \\ x &=\frac{1500 \times 80}{400} \\ x &=15 \times 20 \\ x &=₹ 300 \end{aligned}$
∴ 1.5 kg cake cost = Rs 300
Question 4
i) In 3 months, a man earns rs 18000
In $x$ months, a man earns Rs 30,000
i.e $\frac{x}{3}=\frac{30,000}{18000}$
$x=\frac{30 \times 3}{18}=\frac{90}{18}$
$x=5$
∴ In 5 months , a man earns Rs 30,000
ii)In 3 months , he earns Rs 18000
Let In 7 months , he earns Rs x
$\therefore \frac{x}{18,000}=\frac{7}{3}$
$x=\frac{7 \times 18000}{3}$
$x=7 \times 6,000$
$x=42000$
∴ In 7 months , he earns Rs 42,000
Question 5
Given 12 mangoes weight $24 \mathrm{~kg}$
Then 8 mangoes weight $x \mathrm{~kg}$
$\frac{x}{2 \cdot 4}=\frac{8}{12}$
$x=\frac{8 \times 2.4}{12}$
$x=\frac{8 \times 24}{12 \times 10}=\frac{16}{10}$☻
x = 1.6kg
∴ 8 mangoes weight 1.6kg
Question 6
Given 12 sheets of thick paper = 40 grams
Let x sheets of thick paper $=2 \frac{1}{2} k g$
=$\frac{5}{2} k g$
$\therefore \frac{x}{12}=\frac{5 / 2 k g}{40 g}$
$\frac{x}{12}=\frac{\frac{5}{2} \times 1000}{40} \mathrm{~g}$
$\frac{x}{12}=\frac{5 \times 500}{40}$
$\frac{x}{12}=\frac{5 \times 125}{10}$
$x=\frac{5 \times 125 \times 12}{10}$
x = 750
Question 7
For a distance of 90 km , a bus consumer = 25 litres
Let for a distance of 288km, a bus consumer = x litres
$\begin{aligned} \therefore \frac{x}{25} &=\frac{288}{90} \\ x &=\frac{288 \times 25}{90} \end{aligned}$
$x=\frac{32 \times 25}{10}$
$x=16 \times 5$
$x=80$ litres.
∴ For a distance of 288 km, a bus consumer = 80 litres
Question 8
Given $\frac{4}{5}$ metre cloth costs $₹ 36 .$
Then $2 \frac{1}{5}$ metre cloth costs x
$2 \frac{1}{5}=2+\frac{1}{5}=\frac{10+1}{5}=\frac{11}{5}$
$\begin{aligned} \therefore \frac{x}{36} &=\frac{11 / 5}{4 / 5} \\ \frac{x}{36} &=\frac{11}{5} \times \frac{8}{4} \end{aligned}$
$\frac{x}{36}=\frac{11}{4}$
$x=\frac{11}{4} \times 36$
∴ $2 \frac{1}{5}$ metre cloth costs Rs 99
Question 9
Given 15 men can pack 540 parcels per day
Let x men can pack 396 parcels per day
i.e $\frac{x}{15}=\frac{396}{540}$
$x=\frac{396 \times 15}{540}$
x= 11
∴ 11men can pack 396 parcels per day
Question 10
Given $12 \mathrm{~kg}$ potatoes costs Rs 132
Then $1 \mathrm{~kg}$ potates costs Rs x
i.e $\frac{x}{132}=\frac{1}{12}$
$x=\frac{132 \times 1}{12}$
x=Rs 11
ஃ 1 kg potatoes cost Rs 11
Given $16 \mathrm{~kg}$ potatoes cost Rs 168
then $1 \mathrm{~kg}$ potatoes costs Rs ?
Let the cost $₹ x$.
i.e $\frac{x}{168}=\frac{1}{16}$
$x=\frac{168}{16}$
$x=₹\frac{21}{2}$
x = ₹ 10.5
∴ 1kg potatoes = Rs 10.5
Compared to 1st case , 2nd case is better buy
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