Q2 of 15 Page 118

In a certain type of brass the ratio of measurements of Copper and Zinc is 5:2. Let’s work out what will be the ratio of Copper and Zinc in 28 kg of brass if 4 kg of Copper is added to it.

Given,


The ratio of copper and zinc in mixture = 5:2


Let copper in mixture is “5a”.


So, zinc will be “2a”.


Given that quantity of brass (mixture of copper and zinc) = 28 kg


⇒ quantity of copper+ quantity of zinc = 28


⇒ 5a + 2a = 28


⇒ 7a = 28


Or, a = 4


So, quantity of zinc = 2a = 2×4 = 8 kg


Also, quantity of copper = 5a= 5×4= 20 kg


According to given problem,


If we add 4 kg of copper


Then quantity of copper in mixture = 20+4 = 24kg


So, the ratio of copper and zinc in 28 kg of brass


= 3:1


More from this chapter

All 15 →
1

The ratio of measurements of water and Dettol in 36 litres of water is 5:1. Let’s work out what volume of dettol should be added to the mixture so that the ratio of measurements of water and dettol becomes 3:1.

 3

Bijan babu has made phenyl water solution of 60 litres in which the ratio of measurements of phenyl and water is 2:23. Let’s work out how much phenyl should be added to this solution so that the ratio of measurements of phenyl and water becomes 9:46.

 4

Amina Bibi has prepared masonry mixture with sand and cement in a ratio of measurement 7:1. But after the brick-work it is seen that 72 kg of mixture remains. She has added more cement with this mixture and the ratio of measurement of sand to cement becomes 6:1. Let’s work out the total quantity of cement she has mixed.

 5

The ratio measurements of Copper, Zinc and Nickel in German silver is 4:3:2 respectively. Let’s work out what weight (in kgs) of Zinc should be added to 54 kg of German Silver, so that the ratio of measurements become 6:5:3.