Question

Roby buys cocoa powder every day to make chocolate.
The quantity of cocoa powder bought on Day $1$ is $5$ times the quantity of cocoa powder bought on Day $2$.
The quantity of cocoa powder bought on Day $3$ is $7$ times the quantity of cocoa powder bought on Day $2$.

The quantity of cocoa powder bought on Day 1: ___
The quantity of cocoa powder bought on Day 2: ___
The quantity of cocoa powder bought on Day 3: $7.7$ lb

• A. $1.1lb,5.5lb$
• B. $5.5lb,7.7lb$
• C. $7.7lb,5.5lb$
• D. $5.5lb,1.1lb$

Answer 1

The correct option is D $5.5lb,1.1lb$

Quantity of cocoa powder bought on Day $3=7.7$ lb
Quantity of cocoa powder bought on Day $3=7$ times the quantity of cocoa powder bought on Day $2$
Quantity of cocoa powder bought on Day $3=$ Quantity of cocoa powder bought on day $2\times 7$
Using related division equation:
Quantity of cocoa powder bought on Day $2=$ Quantity of cocoa powder bought on Day $3÷7$
$=(7.7÷7)$ lb
$7.7÷7=1.1$
Quantity of cocoa powder bought on Day $2=1.1$ lb
Quantity of cocoa powder bought on Day $1$ is $5$ times the quantity of cocoa powder bought on Day $2$.
Quantity of cocoa powder bought on Day $1=$ Quantity of cocoa powder bought on Day $2\times 5=1.1\times 5$Quantity of cocoa powder bought on Day $1=5.5$ lb
Hence, option A is correct.