Question

If one grain of rice is 0.03g, how many grains of rice are there in 2500kg of rice? Give the answer in standard form

Answer 1

- One grain of rice has a mass of 0.03g.

- We are required to find the number of grains of rice that make up 2500kg.

- Before we proceed, we need to know the conversion rate from grams (g) to kilograms (kg). This conversion is given below:

`\begin{gathered} 1kg\to1000g \\ \therefore2500kg\to(2500kg)/(1kg)*1000g \\ \\ 2500kg\to2500000g \end{gathered}`

- Now that we have the masses in the same unit, grams (g), we can continue.

- By adding up each grain of rice of 0.03g, we will eventually add up to 2,500,000g. That is:

`0.03g+0.03g+0.03g+\cdots+0.03g=2,500,000g`

- If we assume that there are n-grams of rice whose weight add up to 2,500,000g. This means that we can say

`\begin{gathered} 0.03g* n=2,500,000g \\ \text{where,} \\ n=\text{ Number of grains of rice} \end{gathered}`

- Thus, to find the number of grains of rice, we simply solve the simple expression above. This is done below:

`\begin{gathered} 0.03n=2,500,000 \\ Divide\text{ both sides by 0.03} \\ (0.03n)/(0.03)=(2,500,000)/(0.03) \\ \\ \therefore n=83,333,333.\bar{3}\approx83,333,333\text{ (Since the number of grains cannot be a decimal} \end{gathered}`

Final Answer

The number of grains of rice is

`\begin{gathered} 83,333,333 \\ =8.3333333*10^7\text{ (In standard form)} \end{gathered}`