Answer:
126
Step-by-step explanation:
Let the total number of postcard with stamp on it =x
Out of 350 postcards, x has stamp on it.
Out of 75 postcards, 27 has stamp on it.
Expressing these as a ratio:
350:x=75:27
350/x=75/27
Cross multiply
75x=350*27
x=(350*27)/75
x= 126
Therefore, the the total number of postcards in the box with stamps on them is 126.