XAT 2022 — QA & DI Question 26
Read the following scenario and answer the THREE questions that follow.
âââââââ
The given candlestick chart depicts the prices of a particular stock over 10 consecutive days. A candlestick comprises of a rectangular box pieced by a line. The top and bottom ends of the line respectively indicate the maximum and minimum prices of the stock on that day, while the horizontal edges of the rectangle correspond to the stock's opening and closing prices. If the rectangle is white, the opening price is lower than the closing price, but if the rectangle is black, then it is the other way around.
Using the above information, answer the questions that follow:
I have five 10-rupee notes, three 20-rupee notes, and two 50-rupee notes in my wallet.
If three notes were taken out randomly and simultaneously, what is the probability that at least 90 rupees were taken out?
Answer & solution
- A
- C
- D
- E
The total number of ways of selecting 3 notes from the :
five 10-rupee notes, three 20-rupee notes, and two 50-rupee notes = 10 notes in total.
10C3â ââââââ= 120
The possibilities for the value of the three notes combined is at least 90 :
Rs 50 + Rs 20 + Rs 20 : The possibilities for this selection is:
2C1 . 3C2. Selection of one Rs 50 note from the two and selection of 2 Rs 20 notes from the three.
Rs 50 + Rs 50 + Rs 10:
(2C2) . (5C1) : Selection of two Rs 50 notes from the two and selection of 1 Rs 10 notes from the five.
Rs 50 + Rs 50 + Rs 20:
(2C2) . (3C1): Selection of two Rs 50 notes from the two and selection of 1 Rs 20 notes from the three.
A total of 6 + 5 + 3 = 14 possibilties
The probability is = 7/60.