The weight (in kg) of cubical block of ice 75 cm in length (if one cubic metre of ice weight is 80 kg) is (1) 35

(2) 42.50

(3) 33.75

(4) 40

The weight = 33.75kg

Step-by-step explanation:

Given that  

one cubic metre of ice weight is 80 kg

which is mathematically written as

1m³ of ice = 80 kg

Therefore 75 cm length of  cubical  block of ice =???

First

changing  75 cm to meters, we have  75/100 = 0.75 m

Volume of block = l³= 0.75³ = 0.421875m³

Given that

1m³ = 80kg

0.421875m³=  0.421875 x 80

= 33.75kg

The answer is in the image 

Cost of 7 gallons=$24.50

Cost of 1 gallon=24.50/7=3.5

Cost of 15 gallons=15*3.5=52.5

Cost of 15 gallons will be $52.5

F=ma

where F=force

m=mass

a=acceleration

Here,

F=4300

a=3.3m/s2

m=F/a

    =4300/3.3

    =1303.03kg

Approximately it is aqual to 1300kg

The solution is given in the image below

The wood before starting =12 feet

Left wood=6 feet

Wood used till now=12-6=6 feet

Picture frame built till now= 6/(3/4)

=8 pieces

Therefore, till now 8 pieces have been made.

Salesperson will make 6% of 1800

=(6/100)*1800

=108

Salesperson will make $108 in $1800 sales

The answer is in the image 

tip=18% of 75.45

     =18/100 * 75.45 = $13.581

Tip = $13.581

Let the father's age be x and son's be y

10 years before-

Father age=x-10

sons age=y-10

Given,

x-10=10(y-10)

x-10=10y-100

Given present age of father=40

therefore,

x=40

40-10=10y-100

10y-100=30

10y=130

y=130/10

y=13

Therefore present age of son=13years