Use the middle of the NCERT range for Homo habilis, which is 725 cc…
Contributed by StemPy LabTry it on paper first. A hint, the key idea and the worked solution are here when you need them.
Use the middle of the NCERT range for Homo habilis, which is 725 cc. Homo erectus had about 900 cc, and Neanderthal man about 1400 cc.
- By what percentage is the brain of Homo erectus larger than that of Homo habilis?
- By what percentage is the brain of Neanderthal man larger than that of Homo erectus?
- How many times as large as the brain of Homo habilis is the brain of Neanderthal man? Give the answer to one decimal place.
Need a reminder? The key ideaShow
NCERT brain capacities: Homo habilis to cc, Homo erectus about cc, Neanderthal man about cc. A percentage increase 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. cc, cc and cc.
Plan. Find the increase, divide by the earlier value, and multiply by .
Step 1. (a) per cent.
Step 2. (b) per cent.
Step 3. (c) times.
Answer: per cent; per cent; times.
Check. , the same as the ratio of the last answer.
Watch out. If you divide by the later value, you get a different number. The reference is always the earlier value.
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