few good LCM/HCF qs
Q1. The LCM of two numbers is 2079 and their HCF is 27. If one
of the numbers is of the form 1a(1+a), find the other number.
(a) 248
(b) 128
(c) 297
(d) 336
(e) None of these
Q2. Find the LCM of (x+3)(6x2+5x+4)and (2 x2+ 7x + 3)(x + 3)
Q3. Find the smallest number which is exactly divisible by 1/3, 1/2 , 1/5, 4/11 , 7/17
Q4. Find the number of positive integers which are smaller than 3600, but whose HCF with 3600 is 45 (from kundan/pandey)
a. 42
b. 32
c. 36
d. None of the above
n/a
Q3. Find the smallest number which is exactly divisible by 1/3, 1/2 , 1/5, 4/11 , 7/17
ans is 28
Little Star
n/a
Q2. Find the LCM of (x+3)(6x2+5x+4)and (2 x2+ 7x + 3)(x + 3)
2x^2+7x+3=(x+3)(2x+1)
6x^2+5x+4---> b^4ac<0 so no solution
LCM of two equation=(x+3)^2(2x+1)(6x^2+5x+4)
Little Star
n/a
Q4. Find the number of positive integers which are smaller than 3600, but whose HCF with 3600 is 45 (from kundan/pandey)
a. 42
b. 32
c. 36
d. None of the above
now the number is mutilple of 45 but common between 45xn and 3600 only 45 means n is either prime number or mutiply of two prime number or 3/9/27 because 3600=3^2 x 2^4 x 5^2 means if we can multiply 45x 3 then HCF between 45x5 and 3600 is =45
so number are 45n
n=1/3/7/9/11/13/17/19/21/23/27/29/31/33/37/39/41/43/47/49/51/53/57/
59/61/67/69/71/73/77/79
so total number=31
Lttle Star
n/a
Thanks for the answers
but i could not understand the q1 answers
Q1. The LCM of two numbers is 2079 and their HCF is 27. If one
of the numbers is of the form 1a(1+a), find the other number.
(a) 248
(b) 128
(c) 297
(d) 336
(e) None of these
HCF of two number is 27 means another number divided by 27 so number is 297
297=11*27
sp anoter number is 7*27=189 beacuse LCM is 2079, also 189 in the for of 1a(1+a)
Little Star
n/a
n/a