## If John has exactly 10 coins each of which was minted in 1910 or 1920 or 1930, how many of his coins were minted in

##### This topic has expert replies
Moderator
Posts: 6242
Joined: 07 Sep 2017
Followed by:20 members

### If John has exactly 10 coins each of which was minted in 1910 or 1920 or 1930, how many of his coins were minted in

by BTGmoderatorDC » Wed Oct 20, 2021 6:12 pm

00:00

A

B

C

D

E

## Global Stats

If John has exactly 10 coins each of which was minted in 1910 or 1920 or 1930, how many of his coins were minted in 1920 ?

(1) Exactly 6 of his coins were minted in 1910 or 1920.
(2) Exactly 7 of his coins were minted in 1920 or 1930.

OA C

Source: GMAT Prep

Legendary Member
Posts: 2064
Joined: 29 Oct 2017
Followed by:6 members

### Re: If John has exactly 10 coins each of which was minted in 1910 or 1920 or 1930, how many of his coins were minted in

by swerve » Thu Oct 21, 2021 2:34 pm

00:00

A

B

C

D

E

## Global Stats

BTGmoderatorDC wrote:
Wed Oct 20, 2021 6:12 pm
If John has exactly 10 coins each of which was minted in 1910 or 1920 or 1930, how many of his coins were minted in 1920 ?

(1) Exactly 6 of his coins were minted in 1910 or 1920.
(2) Exactly 7 of his coins were minted in 1920 or 1930.

OA C

Source: GMAT Prep
Statement 1.
Exactly $$6$$ of his coins were minted in $$1910$$ or $$1920.$$
But how many in $$1920?$$
All $$6, 5,4,3, \cdots$$ Or nothing. Not Sufficient $$\Large{\color{red}\chi}$$

Statement 2.
Exactly $$7$$ of his coins were minted in $$1920$$ or $$1930.$$
But how many in $$1920?$$
All $$7,6,5, \cdots$$ Or nothing at all. Not Sufficient $$\Large{\color{red}\chi}$$

Combining 1 and 2:
Let $$1910$$ be $$A$$
$$1920$$ be $$B$$ and $$1930$$ be $$C$$
\begin{align}
\begin{cases}
\end{cases}
\end{align}

Equating $$(1) \& (3)$$, we get
$$C=4$$

And from equation $$(2) \& (3)$$, we get
$$A=3$$

Therefore, $$B=3$$
So, $$3$$ coins were minted in $$1920$$ C

### GMAT/MBA Expert

GMAT Instructor
Posts: 15949
Joined: 08 Dec 2008
Location: Vancouver, BC
Thanked: 5254 times
Followed by:1267 members
GMAT Score:770

### Re: If John has exactly 10 coins each of which was minted in 1910 or 1920 or 1930, how many of his coins were minted in

by [email protected] » Wed Oct 27, 2021 9:04 am

00:00

A

B

C

D

E

## Global Stats

swerve wrote:
Thu Oct 21, 2021 2:34 pm
BTGmoderatorDC wrote:
Wed Oct 20, 2021 6:12 pm
If John has exactly 10 coins each of which was minted in 1910 or 1920 or 1930, how many of his coins were minted in 1920 ?

(1) Exactly 6 of his coins were minted in 1910 or 1920.
(2) Exactly 7 of his coins were minted in 1920 or 1930.

OA C

Source: GMAT Prep
Statement 1.
Exactly $$6$$ of his coins were minted in $$1910$$ or $$1920.$$
But how many in $$1920?$$
All $$6, 5,4,3, \cdots$$ Or nothing. Not Sufficient $$\Large{\color{red}\chi}$$

Statement 2.
Exactly $$7$$ of his coins were minted in $$1920$$ or $$1930.$$
But how many in $$1920?$$
All $$7,6,5, \cdots$$ Or nothing at all. Not Sufficient $$\Large{\color{red}\chi}$$

Combining 1 and 2:
Let $$1910$$ be $$A$$
$$1920$$ be $$B$$ and $$1930$$ be $$C$$
\begin{align}
\begin{cases}
\end{cases}
\end{align}

Equating $$(1) \& (3)$$, we get
$$C=4$$

And from equation $$(2) \& (3)$$, we get
$$A=3$$

Therefore, $$B=3$$
So, $$3$$ coins were minted in $$1920$$ C
Or you could have saved yourself some time and just linked to identical solution on this page: https://gmatclub.com/forum/if-john-has- ... l#p2526921
Brent Hanneson - Creator of GMATPrepNow.com

• Page 1 of 1