2020 AMC 12A Problem 1

Attempt Problem 1 of the 2020 AMC 12A below, then check your answer against the professionally curated solution from LIVE by Po-Shen Loh. You can also try the full timed exam, view all 2020 AMC 12A solutions, or check the answer key.

All problems are used with official legal permission of the Mathematical Association of America (MAA).

Carlos took

70\%

of a whole pie. Maria took one third of the remainder. What portion of the whole pie was left?

10\%

15\%

20\%

30\%

35\%

After Carlos takes his share,

30\%

of the pie remains

Maria removes

\tfrac13

of that

30\%

, so

\tfrac23

of the remainder is left

After Carlos takes

70\%,

the remaining portion is

30\%.

Maria takes one third of this, namely

\tfrac13 \cdot 30\% = 10\%,

leaving

30\% - 10\% = 20\%.

Thus, C is the correct answer.

Problem 1 in other years