There is a really easy way to find this out I can't really help you so if you just look it up on google you should get your awnser
The ratio is 4:3:1
let the ratio be 4x:3x:x
according to the question,4x+3x+x=40
8x=40
x=5
therefore amount of gravel=x*4=5*4=20

amount of sand=5*3=15

amount of cement=5*1=5
Because the surface area is of a 2-D SHAPE to find a area of a 2-D shape is l x w
Multiplying exponents with different bases
First, multiply the bases together. Then, add the exponent. Instead of adding the two exponents together, keep it the same.
Answer:
1. a=2.3
2. b=2.6
3. c=2.3
4.d=2.6
5. e=40
6. f=1/6
7. g=85
Step-by-step explanation: