Solution
- 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:
[tex]\begin{gathered} 1kg\to1000g \\ \therefore2500kg\to\frac{2500kg}{1kg}\times1000g \\ \\ 2500kg\to2500000g \end{gathered}[/tex]- 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:
[tex]0.03g+0.03g+0.03g+\cdots+0.03g=2,500,000g[/tex]- If we assume that there are n-grams of rice whose weight add up to 2,500,000g. This means that we can say
[tex]\begin{gathered} 0.03g\times n=2,500,000g \\ \text{where,} \\ n=\text{ Number of grains of rice} \end{gathered}[/tex]- Thus, to find the number of grains of rice, we simply solve the simple expression above. This is done below:
[tex]\begin{gathered} 0.03n=2,500,000 \\ Divide\text{ both sides by 0.03} \\ \frac{0.03n}{0.03}=\frac{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}[/tex]Final Answer
The number of grains of rice is
[tex]\begin{gathered} 83,333,333 \\ =8.3333333\times10^7\text{ (In standard form)} \end{gathered}[/tex]