Question
There are 15 numbers such that average of first 12
numbers is 65 while the average of last five numbers is 76. Find the 12th number, if the ratio between 11th and 12th number is 13:7, respectively.Solution
Avg of first 12 numbers = 65 → Sum = 12 × 65 = 780 Avg of last 5 numbers = 76 → Sum = 5 × 76 = 380 11th : 12th = 13 : 7 → Let 11th = 13x, 12th = 7x → 11th + 12th = 20x So, Sum of 1st to 10th = 780 − 20x No further info to find x ⇒ 12th = 7x can’t be calculated Hence, Can’t be determined (not enough data)
Quantity of water in a 360 litres mixture (Milk + Water) is 80 litres less than the quantity of milk in it. Find the quantity of water to be mixed so t...
A mixture measuring 720 ml consists of milk and water in an 8:7 ratio. How much water should be added to ensure that the water content is 12.5% greater ...
When 10 litres of water is added to a mixture of milk and water, the ratio of quantity of milk and water becomes 4:5. Instead, if 20 litres of water had...
In a 60-liter mixture of petrol and diesel, the ratio of petrol to diesel is given as p:1. When 8 liters of diesel is added to th...
A 450 ml solution is composed of water and glucose mixed in the ratio of 8:7. Determine the amount of glucose that must be added to the solution so that...
Mixture ‘E’ of salt and water contains salt and water in ratio 6:5, respectively. What will be the ratio of salt to water in mixture ‘E’ when qu...
Quantity of milk is 20% more than that of water in 220 litres mixture (milk + water). If 22 litres milk is added, then find the quantity of milk in the ...
A mixture of lime and water contains 3a liters lime and (a + 40) liters water. Upon adding 20 liters more water, the ratio of quantity of water to that ...
Mixture 'A' consists of 'm' liters of milk, while mixture 'B' includes '11 + m' liters of milk. Determine the ratio in which mixture 'B' to mixture 'A' ...
- A vessel contains mixture in which 25% is water and rest is milk. If 40 liters more water added in vessel, then quantity of water becomes 35% of mixtu...
Relevant for Exams:
