Question
A mixture contains ‘X’ liter milk and ‘Y’ liter
water. If 30 liter of mixture is taken out and replaced with water, then the quantity of milk and water becomes equal. But, if 60 liter of mixture is taken out and replaced with water, then quantity of milk becomes half of the quantity of water. Find the value of X and Y.Solution
Mixture contains total (X + Y) liters ATQ, X– [30X/((X+Y))] = Y– [30Y/(X+Y)]+30  X² + XY – 30X = XY + Y² – 30Y + 30X + 30Y ⇒ X² – Y² = 60X…(i) And, 2[X–60X/(X+Y)]=[Y–60Y/(X+Y)+60] 2X² + 2XY – 120X = XY + Y² – 60Y + 60X + 60Y  2X2+ XY = 180X +Y2  …(ii) Subtract (i) from (ii) X² + XY = 120X  X + Y = 120ℓ   …(iii) But X² – Y² = 60X ⇒ (X + Y) (X – Y) = 60X ⇒ 2 (X – Y) = X ⇒ 2X – 2Y = X ⇒ X = 2Y   …(iv) By using (iii) & (iv) ⇒ Y = 40ℓ And X = 80ℓ
In a school, 40% of the students are girls, and the rest are boys. During the annual sports event, 30% of the girls and 50% of the boys took part. If th...
In a school, 60% of the students are boys, while the remaining 40% are girls. If 70% of the boys and 80% of the girls pass an exam, what percentage of t...
A and B both spend 30% of their income together which is equal to Rs 26400. If income of A is 20% more than that of B, then find the income of B (in Rs)?
If 35% of 40% of 7/5 of a number is 490, then what is 25% of 2/3 of that number?
- Anita spends 18% of her monthly income on rent and 70% of the rest on household expenditure. If she saves Rs. 1,890, then find her monthly income.
- In a school election between two contestant’s 'A' and 'B', 'A' secured 62% of the total votes and won by 7,440 votes. Find how many votes 'B' got.?
A value is first raised by 15% and then reduced by 40%. What is the overall percentage change in the original value?
Vegetables lose water when cooked. Raw vegetables contain 90% water, but after cooking they contain only 50% water. How much raw vegetable is needed to ...
The total strength of school A is 40% more than that of school B. In school A and B, out of total number of students, 25% and 40% respectively are girls...
A book is listed at Rs. 2,400 and the discount offered is 10%. What additional discount must be given to bring the net selling price Rs. 1,800?