Answer:
4 and 5
Step-by-step explanation:
Let the numbers be x and y
If their sum is 9, hence;
x + y = 9 ....1
When reversed
10y+x = 2(10x+y)
10y+x = 20x + 2y
10y - 2y = 20x - x
8y = 19x
y = 10x/8 ...2
Substitute equation 2 into 1;
From 1;
x+y = 9
x +(10x/8) = 9
18x/8 = 9
18x = 72
x = 72/18
x = 4
Since x+y =9
y = 9-x
y =9-4
y = 5
Hence the numbers are 4 and 5
Answer:
Interval?
Step-by-step explanation:
Answer:
Width = 4 m
Length = 7 m
Step-by-step explanation:
given:
perimeter of a rectangle = 22m
L = 3 + W
perimeter = 2L + 2W
perimeter = 2 (3 + W) + 2W
22 = 6 + 2W + 2W
22 - 6 = 4W
W = 16 / 4
W = 4 m
L = 3 + W
L = 3 + 4
L = 7 m
check:
perimeter = 2L + 2W
22 = 2(7) + 2(4)
22 = 14 + 8
22 = 22 ---- OK
Answer:
13.20 min
Step-by-step explanation:
Rate of the reaction is a measure of the rate of decomposition of the compound.
Rate (R) = Concentration (C) ÷ time (t)
C1/t1 = C2/t2
C1 = 52.3% = 0.523
t1 = 8.6 min
C2 = 80.3% = 0.803
t2 = C2t1/C1 = 0.803×8.6/0.523 = 13.20 min (to 2 decimal places)
