Arjun draws a strip of 60 cm for the last 600 million years, with the left end at 600 million years…
Contributed by StemPy LabTry it on paper first. A hint, the key idea and the worked solution are here when you need them.
Arjun draws a strip of 60 cm for the last 600 million years, with the left end at 600 million years ago and the right end at the present. One centimetre is 10 million years. He marks three events of the NCERT account: the invertebrates, 500 million years ago, the fish with strong fins that moved on to land, 350 million years ago, and the end of the dinosaurs, 65 million years ago.
- How far from the left end is the mark for the invertebrates?
- How far from the left end is the mark for the fish with strong fins?
- How far from the right end is the mark for the end of the dinosaurs?
Need a reminder? The key ideaShow
Order in time: first cells, invertebrates, plants on land, fish with strong fins, amphibians, reptiles, mammals. A strip of cm for million years has one centimetre for million years, so a distance from the left end is .
The worked solution
Have you tried it?
Work it out on paper first. It is fine to get stuck or make a mistake: that is how we learn. When you are ready, go through the solution one step at a time, and check each step against your own.
Given. cm stand for million years, so cm is million years.
Plan. Divide a number of million years by .
Step 1. (a) The invertebrates are million years after the left end. cm.
Step 2. (b) The fish with strong fins are million years after the left end. cm.
Step 3. (c) The end of the dinosaurs was million years before the present. cm from the right end.
Answer: cm; cm; cm.
Check. The distance of the dinosaur mark from the left end is cm, which agrees with .
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