Identify the possible number of points of intersection of four lines in a plane
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Solution
Ans: (A, B, C, D)
Maximum number of points 4 lines can intersect are \(^{4}C_{2}=\frac{4!}{2!\times 2!}\)=6
Lines can intersect maximum of 6 points.
A coin is biased so that probability of getting head is more than tail. If coin is to be tossed 3 times, what is the probability that on at least one of the tosses, coin will turn up heads?
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Solution
Ans: (A, E)
We should take negative approach.
Find out the probability of not getting head at all. i.e. getting only tails on all three coins.
1⁄2 × 1⁄2 × 1⁄2 = 1⁄8 is the max probability of getting t son tree coins.
∴ Probability 0 getting ea at least on one corns is greater t an 1 - 1⁄8 = 7⁄8
In how many ways can 6 adjustable rings be worn in 4 fingers of one hand?
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Solution
Ans: (C, E)
n things can be given to r persons is rn ways.
∴ 6 things can be given to 4 fingers in 46 ways. Also 46= 212
Tom and Dick enter into a partnership by investing in some ratio. After one year, Dick invests another $ 3000. At the end of that year, profits are shared in the ratio 3:5. The initial investments of Tom and Dick could be
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Solution
Ans: (B, C, D)
Let initial investment of Tom and Dick be $x and $y. Dick's investment for 2 years will be y + 3000.
∴ Ratio of capital of tom and Dick is \(\frac{x}{y+3000}\) = 3⁄5
5x = 3y + 3000. Hence check for options that satisfy this equation
A milk vendor receives 2 adulterated supplies S1 and S2 that contains 11% and 5% of water respectively. How much of each kind must be taken so as to form 66 liters of mixture containing 90% milk?
Mark two correct options
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Solution
Ans: (C, D)
11% of water in S1
5% of water in S2
Mixture contains 90% milk i.e. 10% water.
By the principle of allegation
∴ The required ratio = 5 : 1
∴ Quantity of supply S1 = \(\frac{5}{5+1}\) × 66 = 55 liters.
Quantity of supply S2 = \(\frac{1}{5+1}\) × 66 = 11 liters.
8 carpenters working 6 hours a day can make some chairs in 30 days. If the same numbers of chairs are made by x carpenters working y hours a day for 30 days, then x and y can be
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Solution
Ans: (A, B, E)
The man hours required for the chairs will be same. Since both jobs are for 30 days, the man hours will be: 8 × 6 = 48 = xy.
PRECISION SYSTEMS purchased 2 robots R1 and R2 to match their weekly production schedule. On Monday, robot R1 produces 900 units. On Tuesday, robot R2 produces 1300 units. Each day thereafter robot R1 produces 8 units for every 5 units R2 produces. By the end of the week, the two collectively manufactured more than 8700 units. The number of units delivered by robot R2 in week could be
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Solution
Ans: (B, D, E)
Total production of units on Monday and Tuesday = 900 + 1300 = 2200
∴ Minimum Total production on the remaining 5 days
= 8700 - 2200 = 6500
R2 will produce \(\frac{5}{13}\) of the remaining products
∴ R2 will produce 1300 + \(\frac{5}{13}\) × 6500
= 1300 + 2500 = 3800 or more units
When a certain integer n is divided by 18, the remainder is 1. Which of the following could not be an integer?
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Solution
The number n is not divisible by 18.
∴ The number n is also not divisible by any of the factors of 18. Since 2, 3, 6, 9 are factors of 18.
∴ (A),(B), (e), (D) will not give integral values.
∴ The answer has to be (A,B, C, D)
Given rectangular box of dimensions 8cm X 6 m X 2cm, the possible lengths of pencils than can be kept in it are?
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Solution
Ans: (A, B, D)
For a rectangular cuboid, maximum length of a pencil is equal to the length of diagonal Diagonal = \(\sqrt{L^{2}+B^{2}+H^{2}}\)
= \(\sqrt{64+36+4}\)
= \(\sqrt{104}\)
= \(\sqrt{26}\) cm
ABC is an equilateral triangle, AC = 2. What are the values of p and q? Select 2 correct options.
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Solution
Ans: (B, C)
Draw a perpendicular from vertex B.
Then BD = altitude
Also AD = DC ∴ AD = 1⁄2AC
Co-ordinate p = AD (co-ordinate) = 1
Co-ordinate q = BD (co-ordinate) = √3