C = # of carpenter hrs , b = # of blacksmith hrs
c + b = 30...c = 30 - b
20c + 25b = 690
20(30 - b) + 25b = 690
600 - 20b + 25b = 690
-20b + 25b = 690 - 600
5b = 90
b = 90/5
b = 18 <== hrs worked as blacksmith
c + b = 30
c + 18 = 30
c = 30 - 18
c = 12 <== hrs worked as carpenter
Answer:
16 hours
Step-by-step explanation:
let t be time, n the number of computers and w the number of workers, then
t = 
← k is the constant of variation
To find k use the condition n = 30, w = 6 and t = 10 , then
10 = 
( multiply both sides by 6 )
60 = 30k ( divide both sides by 30 )
2 = k
t = 
← equation of variation
When w = 5 and n = 40 , then
t = 
= 
= 16 hours
imagine 135/5
which = 27
Emma has 27 of her 5 pence coins
Answer:
it would be 103/25
Step-by-step explanation:
