Maths

1. A map has a scale of 1: 5000 . What actual distance does the length of 4 cm on the map represent ? ( in km )
actual distance=4x5000=20000cm=200m=0.2km

2. Factorize k^2 +28+ 11k
=(k+4)(k+7)

3. If m: n =9:7 , n:p =7:12 . Find m:n:p.
m:n=9:7
n:p=7:12
m:n:p=9:7:12

4. Simplify (1/2ab)^2 (3a^3b) (ab^3)
=(1/4a^2b^2)(3a^3b)(ab^3)
=(3a^4b^4)/(4a^2b^2)
=3a^2b^2/4