Question

What is the total weight of the teddy bear and the car?

(A) $30kg$
(B) $375kg$
(C) $708kg$
(D) $400kg$

Answer 1

Hint:
To find the total weight of the bear and car, use the image to calculate the weights of each of them separately and add them. Start with finding the weight represented by the smallest division in the dial by taking the ratio of weight by divisions. For calculating the reading, multiply the measure of one small division by the number of divisions pointed by the pointer. Use this method for finding weights of bear and car.

Complete step by step solution:
Here in this problem, we are given an image of two weighing scales, one with a teddy bear toy on it and one with a car on it. Both have circular pointers to show the weights in-unit kilogram. Now with this information, we need to find the total combined weight on both of these scales.

For finding the combined weight of bear and car, we need to find the weight of each of them separately and then add them to get the required answer.
Let’s first consider the teddy bear
Here on the circular dial, each $70kg$ is represented by $10$ small divisions, i.e. weight represented by $1$ small division $ = \dfrac{{70}}{{10}} = 7kg$
Therefore,
One small division on the circular dial $ = 7kg$
The pointer is pointing at the $6th$ small division of the dial. So, the weight of the bear can be calculated by multiplying the number of small divisions and the measure of one small division.
$ \Rightarrow $ Weight of teddy bear $ = 6 \times 7 = 42kg$
Now considering the second weighing scale with car
In this circular dial, each $90kg$ is represented by $10$ small divisions, i.e. weight represented by $1$ small division $ = \dfrac{{90}}{{10}} = 9kg$
Therefore,
One small division on the circular dial $ = 9kg$
The circular dial is divided into $80$ equal divisions and the pointer is pointing at the $80 - 6 = 74th$ division.
So, the weight of the car can be calculated by multiplying the number of small divisions and the measure of one small division.
$ \Rightarrow $ Weight of the car $ = 74 \times 9 = 666kg$
Therefore, the total weight of bear and car$ = $ Weight of teddy bear $ + $ Weight of the car
From the above calculations, we can substitute the values in the above equations as:
$ \Rightarrow $ Total weight$ = 42 + 666 = 708kg$

Hence, the option (C) is the correct answer.

Note:
In this problem, calculating the reading shown by the weight measuring device was the most crucial part. The smallest measurement shown by an instrument is called the least count. For measuring the reading, just count the number of divisions and multiplying it with the least count. Be careful while counting the divisions pointed by the pointer. Always count from the increasing side of the zero of the circular scale.