A vessel contains mixture of milk and water in the ratio of 7 : 5 respectively. If 9 liters of mixture taken out and same quantity of water is added, then the ratio of milk to water in remaining mixture becomes 7 : 9, then find the initial quantity of milk in the mixture?

Explanation

sol. Let the initial quantity of milk and water be 7𝑥 𝑎𝑛𝑑 5𝑥 liters. 7𝑥−9 × 7 12 = 5 95𝑥−9 × + 9 12 7𝑥−21 7 4 = 5𝑥−15 + 9 9 4 21 9 (7𝑥−21 ) = 7 (5𝑥+ ) 4 4 63𝑥−189 = 35𝑥+ 147 4 4 4 www.bankersadda.com | www.ssca 28𝑥= 28𝑥= 84 𝑥= 3 Initial quantity of milk = 21 liters S47. ans. (b) Sol. S48. Ans.(c) Sol. Let the cost price is Rs.100a Marked price is Rs.130a Let the discount percentage be 𝑥%. (100 −𝑥) 104 130𝑎× = 100𝑎× 100 100 1300 −13𝑥= 1040 260 = 13𝑥 𝑥= 20% S49. Ans. (a) sol. Let the length of rectangle and side of a square are ′𝑙′ meter. 𝑙2 = 125 + 𝑙× 20 𝑙2 −20𝑙−125 = 0 𝑙= 25𝑚 𝑃𝑒𝑟𝑖𝑚𝑒𝑡𝑒𝑟 𝑜𝑓 𝑟𝑒𝑐𝑡𝑎𝑛𝑔𝑙𝑒= 2 × (𝑙+ 𝑏) = 2 × (25 + 20) = 90 𝑚 S50. Ans. (a) Sol. Let the father’s age be 4𝑥 years. So, Son’s age = 𝑥 years ATQ, 4𝑥+ 3 = 3 × (𝑥+ 3) 𝑥= 6 Let after ‘y’ years, age of father will be 250% of his son’s age. (4 × 6 + 𝑦) = × (6 + 𝑦) 48 + 2𝑦= 30 + 5𝑦 18 = 3𝑦 𝑦= 6 adda.com | www.careerpower.in | Adda247 App