Selina solutions

Selina solutions

Grade 7

Percent and Percentage | Exercise 8(C)

Question 10

Q10) If x is 30% more than y; find :

(i) \frac{x}{y}

(ii) \frac{y+x}{y}

(iii) \frac{y}{y-x}

Solution:

Let y = a

Then x = a\times\frac{100+30}{100}=a\times\frac{130}{100}=\frac{13}{10}a

Now, (i) \frac{x}{y}=\frac{a}{\frac{13}{10}a}=\frac{a\times10}{13a}=\frac{10}{13}

(ii)\ \ \frac{y+x}{x}=\frac{a+\frac{13}{10}a}{\frac{13}{10}a}=\frac{(10+13)a}{10\times\frac{13}{10}a}=\frac{23a}{10}\times\frac{10}{13a}=\frac{23}{13}

(iii)\ \frac{y}{y-x}=\frac{a}{a-\frac{13}{10}a}=\frac{a}{-\frac{3}{10}a}=\frac{a\times10}{-3a}=-\frac{10}{3}

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Question 10

Q10) If x is 30% more than y; find :

(i) \frac{x}{y}

(ii) \frac{y+x}{y}

(iii) \frac{y}{y-x}

Solution:

Let y = a

Then x = a\times\frac{100+30}{100}=a\times\frac{130}{100}=\frac{13}{10}a

Now, (i) \frac{x}{y}=\frac{a}{\frac{13}{10}a}=\frac{a\times10}{13a}=\frac{10}{13}

(ii)\ \ \frac{y+x}{x}=\frac{a+\frac{13}{10}a}{\frac{13}{10}a}=\frac{(10+13)a}{10\times\frac{13}{10}a}=\frac{23a}{10}\times\frac{10}{13a}=\frac{23}{13}

(iii)\ \frac{y}{y-x}=\frac{a}{a-\frac{13}{10}a}=\frac{a}{-\frac{3}{10}a}=\frac{a\times10}{-3a}=-\frac{10}{3}

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