4. 5. The number of ways, 16 identical cubes, of which 11 are blue and rest are red, can be placed in a row so that between any two red cubes there should be at least 2 blue cubes, is............ If the coefficient of x20 in the binomial expansion of 60 is 5k., where l, kN and l Kshitiha is co-prime to 5, then k is equal to... 6. Let 7. A = {(x,y): |x|y,|x|+2y8} and A = {(x,y):|x|+|y|k}: If 27 (Area A) = 5 (Area A2), then k is equal to: If the sum of the first ten terms of the series 1 2 3 4 5 + + 25 65 325 1025 2501 to....... m +......is, where m and n co-prime numbers, then m + n is equal n