Question

Let AB: CD: EF represent the time in a digital clock, where AB is the hours, CD is the minutes and EF is the seconds. In one hour, for how many minutes is the value of C greater than that of D?

Answer 1

Your question=> Let AB:CD:EF represent the time in a digital clock, where AB is the hours, CD is the minutes and EF is the seconds. In one hour, for how many minutes is the value of C greater than that of D?

Answer: 15 minutes

Step-by-step explanation:

C takes the values 0 to 5.

• When C= 0, no value of D is smaller than C.

• When C=1, C> D only when D=0. Thus, the value of C is greater than that of D for 1 minute.

• When C=2, C>D only when D=0,1. Thus, the value of C is greater than that D of for 2 minutes.

• When C=3, C> D only when D=0,1,2. Thus, the value of C is greater than that of D for 3 minutes.

• When C=4, C>D only when D=0,1,2,3. Thus, the value of C is greater than that D for 4 minutes.
• When C=5, C>D only when D=0,1,2,3,4. Thus, the value of C is greater than that of D for 5 minutes.

Therefore, in one hour, the value of C is greater than that of D for 1+2+3+4+5=15 minutes