Answer:
Step-by-step explanation:
You would never buy a 10-pack, because two 5-packs cost less.
To buy 3 bars you need a single bar and a pair of single bars for £0.82 + £0.82+ £0.41 = £2.05
To buy 30 bars you need 3 pairs of 5-bar packs = 3×£5.75 = £17.25
To buy the remaining 5 bars you need one 5-bar pack = £3
cost = £2.05 + £17.25 + £3 = £22.30
Step-by-step explanation:
Answer:
a) - 7 dollars
b) 24.30 dollars
c) - 5 dollars
Step-by-step explanation:
b) 27 / 10%
Divide 27 by 10/100 by multiplying 27 by the reciprocal of 10/100.
27 x 100/10
Multiply 27 and 100 to get 2700.
2700/10
Divide 2700 by 10 to get 270.
270
Divide 270 by 100 to get 2.7
Subtract 27.00 - 2.7 = 24.30
24.30
Answer:
118.1
Step-by-step explanation:
You need to divide 708.6 by 6 to get the amount of chocolate in one day
Answer:
Consider f: N → N defined by f(0)=0 and f(n)=n-1 for all n>0.
Step-by-step explanation:
First we will prove that f is surjective. Let y∈N be any natural number. Define x as the number x=y+1. Then x∈N, and f(x)=x-1=(y+1)-1=y. We conclude that f is surjective.
However, f is not injective. Take x1=0 and x2=1. Then x1≠x2 but f(x1)=0 and f(x2)=x2-1=1-1=0. We have shown that there are two natural numbers x1,x2 such that x1≠x2 but f(x1)=f(x2), that is, f is not injective.
Note:
If 0∉N in your definition of natural numbers, the same reasoning works with the function f: N → N defined by f(1)=1 and f(n)=n-1 for all n>1. The only difference is that you consider x1=1, x2=2 for the injectivity.
