what is the smallest number of integer kilogram weights needed to weigh every whole kilogram between 1kg and 40kg?

9514 1404 393

  4

Step-by-step explanation:

We assume you are using a balance, and that weights can be put in either pan. In that case, weight values can be either added or subtracted, so there are 3 possibilities for the contribution each weight makes. In other words, we need to find how many digits are required to count to 40 in base 3.

The largest 3-digit number in base 3 is ...

  3^2 +3^1 + 3^0 = 13 (base 10)

The largest 4-digit number adds 3^3 = 27 to this: 27 +13 = 40.

Hence, we can weigh values 0 to 40 using 4 weights, of sizes 1, 3, 9, 27.

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Some example weights are ...

  5 = 9 - 3 - 1

  38 = 27 + 9 + 3 - 1

where the "negative" weights are placed in the same pan as the unknown.

6 spoons of sugar for every 21 cups of flour

step-by-step explanation:

option a is correct.

step-by-step explanation:

scale factor: it is used to find proportional measurements.

proportions means having the same ratio.

scale factor is the ratio of the model measurement to the actual measurement in a simplest form.

or we can say that the ratio of any two corresponding lengths in two similar geometric figures

if the scale factor is more than 1, then it is an enlargement,

if the scale factor less than 1, then it is a reduction.

given the two geometric figure:

by definition of proportions, we have