Random Puzzles 

Workings

Hint
I bought at least 6 of each stamp.

Answer
Six lots of 4p, 7p, and 19p, and ten lots of 5p, and 12p.

Reasoning
For three denominations of stamps, I was asked to buy 6 of each, and for the other two denominations, I had to buy 10 of each.

So I had to buy at least 6 of all five denominations.

This would be for a total of 6 x (4 + 5 + 7 + 12 + 19) = 282p = £2.82.

The remaining 68p has to buy the remaining 8 stamps, 4 of each of the two remaining denominations.

If we just bought 1 of each of the two remaining denominations they would have cost 68 ÷ 4 = 17p.

So the two remaining denominations must have been 5p and 12p.

Double-Checking
 6 x  4 =  24
10 x  5 =  50
 6 x  7 =  42
10 x 12 = 120
 6 x 19 = 114

For a total of 24 + 50 + 42 + 120 + 114 = 350p = £3.50.

Workings

Hint
Albert is 6 years old.

Answer
10 years old.

The length of their name in years.

Workings

Hint
Light travels over 186,000 miles each second.

Answer
Miles travelled by light in a second.

Reasoning
Light travels over 186,000 miles per second.

There are 2.54cm in an inch, 12 inches in a foot, 3 feet in a yard, and 1760 yards in a mile. So there are 2.54 x 12 x 3 x 1760 = 160,934.4cm in a mile.

Workings

Hints
The first letters of the words are: D, D, F, I, L, L, P, S, S, S.

Answers
dif + fer + ent = different
dig + est + ive = digestive
far + mho + use = farmhouse
imp + ort + ant = important
lib + rar + ian = librarian
lig + htn + ing = lightning
por + tfo + lio = portfolio
sca + rec + row = scarecrow
sin + cer + ely = sincerely
som + eth + ing = something