Tyler had 23 more postcards than Mason. They had 361 postcards altogether. When Mason lost some postcards, Tyler had 6 times as many as Mason. How many postcards had Mason lost?

Answer 1

T= 23+M

T+M = 361

T= 361-M

361-M = 23+M

2M = 338

M =338/2 = 169

T =23+169 = 192

T=6(M-X)

192= 6(169-X) = 1014 - 6X

6X = 1014-192 = 822

X = 822/6= 137 cards lost