• # question_answer 7) Find the ratio of the following. (a) 30 min to 1.5 h          (b) 40 cm to 1.5 m              (c) 55 paise to  1           (d) 500 mL to 2 L TIPS Firstly, convert both the quantities in same unit and then find required ratio.

(a) Here, we have to convert 1.5 h into min. We know that,  1 h = 60 min $\therefore$ 1.5 h = 1.5 $\times$ 60 min = 90 min $\therefore$Required ratio $=\frac{30\min }{90\min }=\frac{30}{90}$ $\because$$30=2\times 3\times 5$ and  $90=2\times 3\times 5\times 3$ $\therefore$ HCF of 30 and $90=2\times 3\times 5=30$ Ratio $=\frac{30\div 30}{90\div 30}=\frac{1}{3}=1:3$ (b) Here, we have to convert 1.5 m into cm. We know that, m = 100 cm $\therefore$ $1.5m=1.5\times 100cm=150cm$ $\therefore$ Required ratio $=\frac{40cm}{150cm}=\frac{40}{150}$ $\because$ $40=2\times 2\times 2\times 5$ and $150=5\times 3\times 2\times 5$ $\therefore$ HCF of 40 and $150=2\times 5=10$ Ratio $=\frac{40\div 10}{150\div 10}=\frac{4}{15}=4:15$ (c) Here, we have to convert  1 into paise. We know that, ` 1 = 100 paise $\therefore$ Required ratio $=\frac{55paise}{100paise}=\frac{55}{100}$ $\because$ $55=5\times 11$ and $100=5\times 2\times 2\times 5$ $\therefore$HCF of 55 and $100=5=\frac{55\div 5}{100\div 5}=\frac{11}{20}=11:20$ (d) Here, we have to convert Litre into mL. We know that, 1 L = 1000 mL $\therefore$ $2L=2\times 1000\,mL=2000\,mL$ $\therefore$ Required ratio $=\frac{500\,mL}{2000mL}=\frac{500}{2000}=\frac{5}{20}$ [dividing numerator and denominator by 100] Ratio = 1/4 = 1 : 4