Answer:
Step-by-step explanation:
t2/t1=r
-10/2=-5
2*-5=-10
Answer:
Step 1: Calculate the change by subtracting old cost ($50) from the new cost ($64)
Step 2: Divide that change by the old cost ($50). You will get a decimal number
Step 3: Convert the decimal number to a percentage by multiplying by 100%
Step-by-step explanation:
Try this first
400+30+7. +0+4
3,000,000+500+40+3,000+2+1
Answer:
20 hours
Step-by-step explanation:
We can work easier if we think in terms of an hour
the first equation that we can write is
A + B = 1/4 (its meaning is that in an hour A and B fill 1/4 of the cistern)
the second equation we can write is
A + C = 1/5 (its meaning is that in an hour A and C fill 1/5 of the cistern)
the third equation that we can write is
B = 2C (its meaning is that in an hour B fill 2 times C the cistern)
now we can substitute the value of B in the first two equations
A + 2C = 1/4
A + C = 1/5
A = 1/5 - C
1/5 - C + 2C = 1/4
C = 1/4 -1/5
C = (5-4)/20
C = 1/20 (this means that in an hour C will fill 1/20 of the cistern, so it takes 20 hours to fill the entire cistern)
A = 1/5 - 1/20
A = (4-1)/20 = 3/20
B = 1/20 *2 = 1/10
I'll help on 12. You know that 5*5 is 25. therefore what times 5 equals 20?
