3rd Class Mental Ability Days and Dates & Possible Combinations Days and Dates & Possible Combinations

Possible Combinations          

• How to make possible combinations/pairs of 1 - 1 objects from given m - n objects?
• If \[m=n,\]then number of possible (1 - 1) combinations of (m-n) objects are \[m\times m\].
• If \[m\times n\], then number of possible (1 - 1) combinations of (m-n) objects are \[m\times n\].

Days and dates

• How to find the days required in question?
• We have to first naming what is today, yesterday and tomorrow.
• 8^th day from today is again that day.

EXAMPLE

1.    How many possible combinations of one boy and one girl can be formed from 3 boys and 6 girls?

(a) 18                           (b) 12                           (c) 15                           (d) 24

Explanation (a):      

There are 3 boys and 6 girls: \[{{B}_{1}},\text{ }{{B}_{2}},\text{ }{{B}_{3}}\] and \[{{G}_{1}},{{G}_{2}},{{G}_{3}},{{G}_{4}},{{G}_{5}},{{G}_{6}}.\]

Possible Combinations: (\[{{B}_{1}}{{G}_{1}},\text{ }{{B}_{1}}{{G}_{2}},\text{ }{{B}_{1}}{{G}_{3}},\,\,{{B}_{1}}{{G}_{4}},\,\,{{B}_{4}}{{G}_{5}},\,\,{{B}_{1}}{{G}_{6}},\,\,{{B}_{2}}{{G}_{1}},\,\,{{B}_{2}}{{G}_{2}},\,\,{{B}_{2}}{{G}_{3}},\]\[{{B}_{2}}{{G}_{4}},{{B}_{2}}{{G}_{5}},\text{ }{{B}_{2}}{{G}_{6}},\text{ }{{B}_{3}}{{G}_{2}},\,\,{{B}_{3}}{{G}_{3}},\,\,{{B}_{3}}{{G}_{4}},\,\,{{B}_{3}}{{G}_{5}},\,\,{{B}_{3}}{{G}_{6}}\])

Number of possible combinations = 18

2.    If today is 3^rd day from Sunday, then what day is today?

(a) Tuesday                 (b) Wednesday            (c) Thursday                (d) Friday

Explanation (a):    

Today from Sunday and 3^rd day from Sunday is Tuesday is Tuesday [Sunday, Monday, Tuesday] today is Tuesday.