How many numbers greater than 150 can be formed from the ...
How many numbers greater than 150 can be formed from the digits 1, 2, 3, 4, 5 without repetition?
91
191
291
391
Correct answer is C
Note that every 4- digit and 5- digit numbers formed is greater than 150. Therefore, 5P5+5P4=5!(5−5)!+5!(5−4)!=120+120=240 numbers are greater than 150 already.
Among the 3- digit numbers, the numbers 123, 124, 125, 132, 134, 135, 142, 143 and 145 are removed from the ones that meet the criterion so we have:
5P3−9=5!(5−3)!=60−9=51⟹240+51=291 numbers are greater than 150.
If P = (23−41), Q = \(\begin{pmat...
If 36, p,94 and q are consecutive terms of an exponential sequence (G.P), find the sum ...
Find the radius of the circle 2x2+2y2−4x+5y+1=0...
A stone is thrown vertically upwards and its height at any time t seconds is h=45t−9t2. F...
Given that a=i−3j and b=−2i+5j and c=3i−j, calculate |a−b+c|....
Given that f(x)=2x3−3x2−11x+6 and f(3)=0, factorize f(x)...
P, Q, R, S are points in a plane such that PQ = 8i - 5j, QR = 5i + 7j, RS = 7i + 3j and PS = x...