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Quantitative Aptitude Quiz 5
3 questions
- How many kgs of Rice costing Rs. 10 per kg be mixed with 24 kgs of Rice costing Rs. 16 per kg so that the resulting mixture is sold at Rs. 14 per kg
- 8
- 12
- 16
- 24
Show the answer
Answer: 12
Let Rice at Rs. 10/kg be R1 and Rice at Rs. 16/kg be R2. Since the mixture is sold at a mean price of Rs. 14 per kg, the ratio of the two varieties of rice in the mixture is given by,
R1 : R2 = 16 - 14 : 14 - 10 = 1 : 2
i.e, R1 is mixed with R2 such that in a 3 kgs of the mixture R1 is 1 kg and R2 is 2kg.
Now, Let the amount of R1 in the mixture containing 24 kgs of R2 be $x$, then
$x$ : 24 = 1 : 2
x = 12 kgs
- A bag contains 10 white balls and 6 black balls. Find the probability that 2 balls picked at random are of same colour.
- $\frac{3}{4}$
- $\frac{2}{5}$
- $\frac{1}{2}$
- $\frac{5}{8}$
Show the answer
Answer: $\frac{1}{2}$
S : sample space.
n(S) : Total number of possible outcomes when two balls are picked = $^{16}C_2$W : Ball picked is white.
n(W) = Total Number of ways in two white balls are picked from 10 white balls = $^{10}C_2$B : Ball picked is black.
n(B) = Total Number of ways in twoblack balls are picked from 6 black balls = $^{6}C_2$Probability that two balls picked at random are of same colour = $\frac{n(W) + n(B)}{n(S)}$
= $\frac{^{10}C_2 + ^{6}C_2}{^{16}C_2}$
= $\frac{60}{120}$ = $\frac{1}{2}$
- After how many years will an amount invested at 5% SI p.a double itself.
- 6
- 14
- 10
- 20
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Answer: 20
If an amount doubles itself at simple interest, then the interest obtained will be equal to the principal invested. Hence SI = P.
Using the formula for Simple Interest
SI = $\frac{\text{P x r x t}}{100}$
P = $\frac{\text{P x 5 x t}}{100}$
t = $\frac{100}{5}$
t = 20 years
Hence the amount doubles itself after 20 years.