Cardinality of R3: 85. How?

[Roby Ajith]

Let S be the set {January, February, March, April, May, June, July, August, September, October, November, December} of months in a year. Define the following three relations:  

• R1:={(a,b)|a,b∈S, a and b have same last four letters. }
• R2:={(a,b)|a,b∈S,R2:={(a,b)|a,b∈S, a and b have same number of days. }
• R3:={(a,c)|a,c∈S,R3:={(a,c)|a,c∈S, for some b∈S,(a,b)∈R1,(b,c)∈R2}b∈S,(a,b)∈R1,(b,c)∈R2}

How the cardinality of R3 is calculated as 85?

Please help

Roby

[subhajit POD]

Hi Roby, Please go thorugh the solution provided in the portal. Hope it will help. This question has been discussed many times earlier. Please take a look at those if you want. 

Best

Subhajit

[Samridh Srivastava]

Hi 

I wanted to ask wether we will be able to operate the scientific calculator by TCS from numpad on keyboard or will we hv to use the mouse.

On my desktop it’s not working from numpad as a result calculations are taking much more time.

Thank You.

[Debajyoti Biswas]

Samridh,

It works with mouse only