Lucas collects marbles. every time lucas buys forty marbles for four dollars, his grandmother buys lucas twenty marbles for two dollars. if lucas buys two hundred marbles, how many marbles does his grandmother buy for him? how much money does lucas spends for his two hundred marbles?

40 marbles = $4 + 20 marbles = $2
40x5 = 200 $4x5 = $20 + 20x5 = 100 $2x5 = $10
Lucas spent $20 on his marbles and his grandma got him 100 marbles

The first one, i believe, would be correct. all the others have one thing in common, and that's that they have repeating numbers. in the second one, x and y have repeating 6's and 3's, and in the third, x and y have repeating 6's as well. in the last one, there are repeating 3's. the first one has no repeating numbers.

Ithink it is 7. 16