4. Data sufficiency question:
What will be the percentage profit of selling one liter milk.?
1) 16 liter of milk is sold at cost price after adding 20% water to it.
2) the cost price of one liter milk is Rs.16.
Let us assume one liter costs Rs.1. So C.P = Rs.16
When 20% water is added, then total volume = 20 liters. So SP = 20. Profit can be calculated.
Statement 1 is sufficient.
Statement 2 is not required.
5. y=x/(x-k),where k is a constant,and x is real number.show that.
1.y increase with increase in x.
2.y decreases first and then increase with the value of x.
3.y increase then decrease with the value of x.
4.it remains constant.
Typical question. Taking k =5 and we draw the graph,
If x increases y decreases but when x equal to k, y value becomes infinite. But when x is greater than k, y value slowly reaches to 1. So it decrease from infinite to 1.
6. What is the maximum value of vx – yz. If the value of v,x,y,z have to be chosen from the set A where A(-3,-2,-1,0,1,2,3)
d) none of these
To maximize the value of vx – yz, we make yz negative and vx as maximum as possible using given value.
vx−yz=(−3)2−(−3×2)vx−yz=(−3)2−(−3×2) = 15
7. Given a Number 123456, from this number put any three values in numerator and remaining three are in denominator. So how many values you can make from this number less than 1/5.
If the given value is 120, then denominator should be slightly greater than 600. If for 130, it is 650. So if we take numerator as 132, then denominator should be greater than 660 which is not possible as we have only 5 and 4 available. So numerator is less than 130. The following numbers are possible.
123/654, 123/645, 124/635, 124/653, 125/634, 125/643.
8. A square was given. Inside the square there are white tiles and black tiles. Black tiles was among the diagonal of the square and dimensions of both white as well as black tiles is 1cm x 1cm. If there are 81 black tiles in the square. Then find the no of white tiles in it.
In a square, number of squares on the diagonal is equal to the tiles on a single row. If there are even number of square on a side, then total squares on the diagonal is 2n – 1, otherwise 2n. As the total tiles on the diagonal are given as 81, then number of tiles on a side = 2n – 1 = 81 so n = 41.
So number of white tiles = 412−81=1681−81412−81=1681−81 = 1600