Question

Which Japanese city did Americans dropped an atomic bomb at the end of World War II that killed 140,000 Japanese?

Answer 1

There were two cities Hiroshima and Nagasaki on which an atomic bomb was dropped.

Explanation:

By 1945 President Truman concluded that an invasion of Japan, given the fanatical defence shown by the Japanese in islands the Americans took control of, for example Iwo Jima, Saipan and Okinawa, would lead to an unacceptable loss of American life, possibly 250,000

The decision was therefore taken to drop an atomic bomb. On August 6th 1945 the American B-29 bomber Enola Gay dropped Little Boy on Hiroshima. In the face of the failure of the Japanese to surrender, 3 days later Fat Man was dropped on Nagasaki.

Estimates of the deaths which resulted vary enormously but of the two bombs Fat Man was the more powerful, so Nagasaki is your more likely answer.