Here are two offers for batteries.
OFFER B
Pack of 4
£2.52
1/3 off

OFFER A
Pack of 5
£2.75
Pay for 3 packs get 1 free

Zak wants to buy 40 batteries.
Which is the cheaper offer?
You must show your working.

OFFER A is cheaper.

Step-by-step explanation:

Given,

OFFER A

Pack of 5

£2.75

Pay for 3 packs get 1 free

And

OFFER A

Pack of 5

£2.75

Pay for 3 packs get 1 free

To find which offer is cheaper.

For OFFER A

For 4 Packets he needs to pay £2.75

He needs to buy 40 batteries.

He needs to buy 40÷(4×5) = 2 packets.

Total cost = £2.75 ×2 = £5.5

For OFFER B

For 4 Packets he needs to pay £2.52

He needs to buy 40 batteries.

He needs to buy 10 packets.

After discount he has to pay = £2.52 -(£2.52 ×) = £1.68

Total cost = £1.68×10 = £16.8

Hence,

OFFER A is cheaper.

x = ±sqrt(10)

step-by-step explanation:

5 - 2x² = -15

subtract 5 from each side

5-5 - 2x² = -15-5

-2x^2   = -20

divide by -2 on each side

-2x^2   /-2= -20/-2

x^2 =10

take the square root on each side

sqrt(x^2 )=±sqrt(10)

x = ±sqrt(10)

check:

5 - 2x² = -15

+sqrt(10)

5 - 2(sqrt(10))² = -15

5 -2(10) = -15

5 -20 = -15

-15 = -15

-sqrt(10)

5 - 2(-sqrt(10))² = -15

5 -2(10) = -15

5 -20 = -15

-15 = -15

the answer is

d.

5.3066 m2

step-by-step explanation: