You write it: 150 000 000.
One hundred and fifty million years.
150 Million is 150 x 106 or 150,000,000
It would have been 149,997,988 years BC (in 2013). But, assuming that 150 million is, at best, accurate to the nearest million years, for all intents and prposes, the answer should be 150 million years BC.
It is: 1.5*1020
Allosaurus fossils date to between 155 and 150 million years ago. Presumably they died out around 150 million years ago.
150 Million is 150 x 10^6 or 150,000,000
150,000,000 150 million
The youngest known fossils of Apatosaurus date to 150 million years ago. Thus, Apatosaurus probably died out around 150 million years ago.
150,000,000 Euros
About 17,123 years.
A better question could be 'how do write write' but I think the answer you're looking for is '150,000,000'
150 millions years ago Earth was in the late Jurassic period.