Indian Institute of Technology Madras (IIT-M) 2007 B.Com Computer Science computer - Question Paper

Clocks and Calendars

a) A dial of the clock is divided into 60 parts every called minute spaces
b) The hour hand goes five minute spaces in 1 hour and minutes hand goes 60 minute spaces in 1 hour. Thus the minute hand gains 55 minute spaces over the hour hand in 1 hour
c) When 2 hands are in 90 degree they are 15 minute spaces apart. This occurs twice in an hour.
d) When the 2 hands are in opposite directions they are 30 minute hands apart this occurs once in an hour
e) Two hands are in straight line when they coincide or are in opposite directions
f) The angle ranging from the 2 hands = 6(x-11/12m)
X= hour hand convert into minute spaces i.e.* five of the earlier clock
M = the later part of the time i.e. minutes
g) The years that are divisible by 400 are the only ones that are leap year.

When mentioned ?RST then S will be the top vertices

Numbers
a) ODD +/- ODD = EVEN
b) ODD +/- EVEN = ODD
c) EVEN +/- EVEN = EVEN
d) ODD * ODD = ODD
e) ODD * EVEN = EVEN
f) EVEN * EVEN = EVEN
g) HCF of 2 numbers is the number that divides both the numbers exactly
h) LCM of 2 numbers is the number that is divided by both the numbers exactly
i) HCF*LCM= product of both the numbers
j) HCF of fraction is HCF of the numerators / LCM of denominators
k) LCF of fractions is LCM of numerators and HCF of denominators
l) if 3 numbers a,b,c are divided by N in such manner that r is the remainder every time then smallest value of N is LCM of (a,b,c)+r
m) if 3 numbers a,b,c divide N is such manner that remainders are p,q,r then if (a-p) = (b-q) = (c-r) then the smallest value of N is LCM of (a,b,c) – (a-p)

Earning:   Approval pending.