Answer:
since the unknown amount can buy 100 pencils
he bought 70 pencils
therefore $4.50 can buy 30 pencils
so 1 pencils cost $4.50 /30=0.15
Answer:
The answer is 1.65
Step-by-step explanation:
−2.25−(−3.9)
=−2.25−(−3.9)
=−2.25+3.9
=1.65
Answer:
Step-by-step explanation:
You can split the coins into 3 groups, each of them has 3 coins. Weigh group 1 vs group 2, if one is lighter, that group has the fake coin. If both groups weigh the same, then group 3 has the fake coin.
Continue to split the group that has the fake coin into 3 groups, each group has 1 coin. Now apply the same procedure and we can identify the fake coin.
Total of scale usage is 2
b) if you have
coins then you can apply the same approach and find the fake coin with just n steps. By splitting up to 3 groups each step, after each step you should be able to narrow down your suspected coin by 3 times.
Step 1: you narrow down to group of
coins
Step 2: you narrow down to group of
coins
Step 3: you narrow down to group of
coins
...
Step n: Step 1: you narrow down to group of
coin
Use the equation (x2-x1)/(y2-y1)
Substitute the value of x and y
Answer:
Step-by-step explanation: