In a bag there are 5 red, 3 white and 4 black balls. Four balls are drawn from the bag. The number of ways in which at most 3 reel balls are selected is

At most 3 red balls can be drawn in the followingways Number of red balls  Other colour balls  Number of ways 04 7C413 5C1×7C322 5C2×7C231 5C3×7C1Hence, required number of ways=7C4+5C1×7C3+5C2×7C2+5C3×7C1=35+175+210+70=490