Answers are mentioned along with explanations/
Explanation:
1. We are given D = 5R
where D = no. of diamonds and R = no. of rubies
a. In words, Number of diamonds = 5 times no. of rubies
In letters D = 5R
b. Given R = 4, so D = 5 x R = 5x 4
D = 20
c. Given R = 10 , so D = 5 x R = 5x 10
D = 50
d. Given D = 15 , D = 5R so , R = D/5 = 15/5 = 3
R = 3
e. R = 
because D = 5R
2. Given A = B + C
a. B = 5 , C = 2 => A= 5+2 => A= 7
b. B = A - C from above equation and given A = 10 , C = 2 , B= 10 - 2
B = 8
c. two values of B and C for A to be 7
B = 4 C = 3 and vice versa as 4+3 = 7
d. B = A - C by moving C on the RHS thus changing its prefix sign.
3. Given A = 3x and B = 5x+1
a. B goes up faster because it is 5 times x plus 1 where A is just 3 times x
b. if x = 0, A = 3x = 3x0 = > A = 0
c. if x =1 , B = 5x+1 = 5x1 +1 = 5+1 => B = 6
4. Given A = 2x and B = x2 where x2 means x*x so,
a. if x=1 , A = 2*1 = 2 and B = 1*1 = 1
b. if x = 3, A = 3*1 = 3 and B = 3*3 = 9
5. Given D =2R
a. given R = 8 , D = 2*8 => D=16
b. given R =3 then D = 2*3 => D = 6
c. D= 20 given, R = D/2 = 20/2 => R = 10
d. D = 100 so R = D/2 = 100/2 => R =50
e. R = 
or D/2
6. Given C = π D and π = 3.14
a. if D = 20, C = 3.14*20 => C = 62.8 centimeters
b. if D = 10, C = 3.14*10 => C = 31.4 inches
c. Given C = 18, D = C/31.4 = 18/3.14 => D = 5.732 inches
7. Given S = D/T
a. S = 12/3 = 4 feet/seconds
b. S = 100/5 = 20 miles/seconds
c. For S = 4feet per second , D = 8 ft and T = 2 seconds as S = D/T
4
Get Answer
21
