84 oranges - 24 rotten = 60 oranges that are either ripe or unripe Let x = number of unripe orangesLet x + 18 = number of ripe oranges You know that the number of ripe oranges plus the number of unripe oranges is equal to 60 (x) + (x + 18) = 60 Subtract 18 from each side x + x = 42 x + x is the same as 2x, so 2x = 42 Divide each side by 2 2x/2 = 42/2 The 2s on the left side cancel out x = 21 So the number of unripe oranges is 21 The number of ripe oranges is x + 18,which is 21 + 18 = 39 So the number of ripe oranges is 39
